It was the morning after the night before for Argentinian fans in Nizhny Novgorod on Friday and the recriminations from the devastating Croatia defeat just hours earlier were well underway.

The realisation that the 3-0 thumping by Croatia -- complete with comedy first goal -- had left the mighty two-time winners on the verge of a humiliating exit, left some of their fans in tears.

On Friday, many remained stunned by what had happened.

"We can't sleep, we can't talk, we can't do anything," said Sebastian, a 34-year-old lawyer who had travelled to Russia from Rosario.

"We've never seen anything like last night."

The team, he said, had shown no "huevos", using the Spanish slang for testicles.

Susi, a grandmother from Buenos Aires who spent an eye-watering $40,000 taking her son and grandson to Russia, said the result was so bad it could have implications for Argentina's president, Mauricio Macri, as he battles economic problems at home.

"If Argentina loses, it can become a social problem," she said.

The defeat was arguably the most shocking result of the tournament so far.

A team thought among the favourites for the World Cup, with superstar Lionel Messi as captain, were not expected to struggle through the first stage.

They certainly weren't expected to play so badly.

The result was Argentina's worst at a World Cup since being dismantled by Johan Cruyff's "Total Football" Dutch side 4-0 on a thundery night in West Germany back in 1974.

Nor were Argentina meant to rely on the results of Iceland or Nigeria just to remain in Russia.

With one point from two games, their fans were desperate for Nigeria to beat Iceland in Friday's game to retain hope of qualifying for the knockout stage.

"Today, all my country is Nigerian," joked Nicolas, 41, a company owner from Buenos Aires.

Fans of the "Albiceleste" could be spotted all around Nizhny on Friday.

Some were walking round town in kit, others with "Lio" shaved into their hair, and those draped in the country's flag, like Santiago, a student from the south of Argentina, as he prepared to head to Saint Petersburg for Argentina's crucial final Group D match on June 26.

Who was to blame? The embattled coach Jorge Sampaoli or the curiously listless players who have failed to produce, including the great Messi?

"I believe that the coach is not sure what he wants, or he is unable to pass this onto the players," said Santiago.

"But they also have to play, after all they are professionals."

- Down, but not out -

Despair though had turned to hope in the cold light of day, or at least the first signs that all was not lost

Cousins Juan and Valentino from Cordoba were about to embark on a 20-hour journey by train and plane via Moscow, Rome, Madrid and Buenos Aires to go home.

Their Russian odyssey was over but maybe not their team's.

Valentino complained that the Argentinian public and media put too much pressure on the side.

"The people think that the only way is to win the World Cup, they don't consider it a probability to lose," said Valentino, a 19-year-old student.

Juan called for as many as five changes in the team for the Nigeria game.

"We have a potential chance, it's time to support the team," said the 37-year-old accountant hopefully.

"We were in the same situation as we are now (when qualifying for the World Cup).

"We did it one time, so we can do it again."

Veteran Argentina midfielder Javier Mascherano insists relations between the players and coach Jorge Sampaoli are not strained after reports of unrest within the team camp.

Sampaoli was roundly criticised for his game plan following a 3-0 loss to Croatia in Argentina's second group game at the World Cup, sparking rumours the 58-year-old would be sacked during the tournament.

"The relationship with the coach is completely normal," Mascherano said ahead of the must-win match against Nigeria in Saint Petersburg on Tuesday.

"Obviously, when we feel uncomfortable about something we speak with him because if we didn't we would be hypocrites."

Argentina were on the brink of elimination after the Croatia mauling but victory against Nigeria would send them through as runners-up in Group D if leaders Croatia avoid defeat against Iceland.

"We know the situation is tricky," Mascherano said. "We have to be united, to express our opinions, and do everything possible so the team goes into the game in the best position."

Argentine Football Association (AFA) president Claudio Tapia has given his backing to Sampaoli after holding a meeting with the embattled coach on Friday, a team source revealed.

Franco Armani is tipped to replace Willy Caballero for the Nigeria clash after the Chelsea goalkeeper's blunder against Croatia, with Sampaoli also expected to ditch his three-match defence and return to a traditional back four.

Russian police said early on Wednesday they had received multiple bomb threats in the World Cup host city of Rostov-on-Don, causing bars and restaurants to be evacuated across the city.

"On June 26, police received a series of phone calls about explosives planted at locations in Rostov-on-Don," local police said in a statement.

"Police forces made all the necessary checks and no dangerous objects were found," the statement said. "Currently, all the venues are operating normally."

Increasingly isolated on the global stage, Russia is keen to use the World Cup to project an image of stability and strength. Authorities have vowed to host a safe event and any security incidents involving fans could jeopardise Moscow's efforts.

A policeman at the Topos Congress-Hotel in Rostov-on-Don, which was evacuated at around 2000 GMT on Tuesday, said 16 venues had been evacuated across the city as part of a drill.

On the other side of the city, a manager at the Luciano Italian restaurant said staff had been told to evacuate the building for around two hours after receiving a bomb threat.

"There was a phone call, an anonymous phone call, they said there was a bomb in the building," said the manager, who declined to give their name because they were not authorised to speak to the media.

A spokesman for soccer's world governing body FIFA was not immediately available for comment.

The Russian city of Rostov-on-Don, some 955 km (593 miles) south of Moscow, has so far hosted four matches in the World Cup, including Croatia's 2-1 win over Iceland earlier on Tuesday. The next scheduled match at the venue is on Monday.

The city is just a short distance from Russia's border with eastern Ukraine, where rebels backed by Moscow have been fighting Ukrainian troops since 2014, and its close proximity to the conflict had caused security concerns ahead of the tournament.

The Topos Congress-Hotel is listed as an official World Cup hotel by FIFA, but none of the competing teams are staying there, according to official documents.

Police at the scene said the hotel had been evacuated due to a bomb threat and sniffer dogs were seen entering the building, a Reuters witness said.

Security services were seen questioning people on the street outside the hotel, next to emergency vehicles and a crowd of around 60 evacuated guests who had not yet been allowed back into the building.

Russia was subject to a wave of hoax bomb threats last summer, causing disruption at businesses and public buildings in towns and cities across the country.

The Russian Federal Security Service said in October it had identified four Russian citizens behind the hoax campaign, who were living abroad and using internet phone services to call in the threats anonymously.

Argentina legend Diego Maradona wished Lionel Messi on his 31st birthday through an Instragram post. Maradona posted a picture of him with Messi and captioned the image with a short dedication that read `Happy Birthday, Leo Messi’ accompanied by two emoji gifts:  a cake and an arm with a closed fist, as a sign of strength.

Maradona Supported Messi on his last match against Croatia, where the Argentine playmaker came under intense criticism from his countrymen.

Messi’s team mates and friends also celebrated his birthday, he was presented with birthday cake by Argentina team-mates as some of them posted some pictures with Messi on social media. Sergio Aguero wished Messi a happy birthday with a post on his Instagram. The 31-year-old also took time out to meet some of his team-mates' children.

Argentina are gearing themselves up for their final group game against Nigeria which will be held tomorrow at 12 pm in Bangladesh time.

France midfielder Paul Pogba said the finals in Russia might be his last World Cup but he hopes he will be fit for more.

"It might be my last World Cup," the Manchester United player, 25, told a news conference ahead of Tuesday's Group C final game against Denmark.

France have already qualified for the last 16 and will secure top spot if they avoid defeat.

"I'm realistic, we don't know if I'll be called up, maybe other players will be better than me," added Pogba.

"I hope I'll play more. I've already had the chance to play two, some can only dream to play one."