Moroccans have been flying into Qatar for their team's knockout World Cup match against Spain on Tuesday even as fans already in the country have been scrambling for tickets, adding to demand for seats in a potential challenge for the organisers.

The last Arab and African side left in World Cup, Morocco has been willed on by some of the most impassioned fans at the tournament, many of whom live and work in Qatar and are hoping to see their team advance to its first quarter final.

But Morocco's matches have also been testing for organisers: there was pushing and shoving outside the stadium as ticketless fans gathered ahead of its Dec. 1 defeat of Canada, with some trying to climb the fence.

Desperate to attend the match against 2010 champions Spain, more than 1,000 Moroccan fans gathered at the official ticketing office on Monday night. Reuters journalists saw at least two scuffles and riot police deploy as the crowd swelled.

One fan said many had left empty-handed.

Some said they had come after seeing social media posts saying the Moroccan embassy and football association would distribute free tickets. Reuters could not reach the Moroccan football federation for comment.

The Moroccan embassy said on Twitter that it had handed out 500 tickets to Moroccans living in Qatar. The Moroccan football team's official Facebook page had said FIFA had made 5,000 extra tickets available for Morocco fans.

Some have struck lucky, saying they had got tickets from the Moroccan football federation.

One of them was Mohammed-Tayyeb Muhyi, who said he got his ticket after landing in Qatar on Tuesday. He said he had neither a flight nor a match ticket 24 hours earlier.

"We're in a dream," he said.

'STAY CALM'

Another Morocco fan, Houda Belkadi El Haloui, who has been in Qatar for three weeks, said she also got a ticket from the football federation after it called her and told her to collect it from a coffee shop.

"I had a chance to get one, but I am very afraid for my other brothers and sisters that they will be blocked outside of the stadium. I'm very afraid. I hope the Moroccan supporters will understand that there is a problem ... I ask them to stay calm."

While Morocco, in the last 16 for the first time since 1986, is the underdog, the support of its vociferous, red-clan fans has been seen as a big asset in the first World Cup hosted by an Arab state.

"Atlas Lions carry hopes of a whole continent," the Moroccan newspaper Maroc Le Jour declared in a front-page headline.

Royal Air Maroc said on Friday it was laying on four extra flights with 270-340 fans on each.

The Moroccan consulate has asked fans to "show sportsmanship regardless of the result" and to avoid doing anything that could trigger incidents with Spanish fans.