A suspected suicide bomber sneaked into a Rab barrack and blew himself up in the capital's Ashkona yesterday, in what appears to be the country's first such attack by a terror suspect inside a law enforcement agency's compound. 

Terror group Islamic State claimed credit for the attack, reports BBC Bangla. 

The attacker, who is yet to be identified, died instantly while two Rab members suffered splinter injuries. 

All prisons across the country have been put on alert while security has been stepped up at all domestic and international airports and Rab offices following the attack.

Hours after the incident that happened around 1:00pm, At-Tamkin, a pro-Islamic State Bangla blog, said in a post that the attack “was carried out by an explosive belt”.

US-based SITE Intelligence, which monitors jihadist activities, also reported the attack.

Both At-Tamkin and SITE cited Amaq, the Islamic State's news agency, as their source.

The Bangladesh government denies IS's presence in the country.

Contacted, Home Minister Asaduzzaman Khan Kamal said, “It's propaganda and an attempt to force the IS brand on us….  Why would the IS come here?”

Police chief AKM Shahidul Hoque and Rab chief Benazir Ahmed visited the scene in the evening, but they did not speak with reporters while leaving the compound.   

It comes a day after a police raid in a “militant den” in Chittagong's Sitakunda. Police claimed that four suicide bombers, including a woman, were killed as they attempted to swoop on SWAT members.    

Since 2005, there have been at least seven suicide bombings at mosques, cultural events and courts or during raids by law enforcers. But no establishments of any law enforcers have ever come under such attacks. 

Yesterday's blast was so powerful that it ripped apart the suspect's torso and sent pieces of him flying in all directions for about 15-20 metres, Rab and police sources said.

The rear windshield of an SUV of Rab headquarters parked near the scene was shattered from what Rab said was the impact of the explosion.

Pictures of the scene released by law enforcement agencies showed the body of the badly mutilated suspect, who was wearing black pants and a white striped shirt. He appeared to be in his late 20s.

The attacker blew himself up when two Rab members challenged him after he entered the premises climbing the boundary wall.

Rab officials later found an unexploded bomb near the body and defused it safely, said Mufti Mahmud Khan, director of the force's Legal and Media Wing.

He said the suspect was thought to be a militant but it was not clear which group he belonged to.  

Briefing reporters at the barrack, Mufti said the two wounded Rab men -- constable Arif and lance corporal Mizan -- were taken to the Combined Military Hospital with minor splinter injuries.

The barrack is also the proposed site for the Rab Headquarters. Currently, it is mostly an empty space fenced by brick walls. Inside, a large barrack is situated where a couple of hundred Rab officials live in tin shacks.

“A stranger trespassed into the premises around 1:00pm, right before the noon prayers, climbing over the boundary wall on our right side. There's a space near the boundary, where our admin officials wash clothes and take shower,” he said. 

“They [officials] challenged the man and asked where he was going and why he was there. The man turned away and tried to escape and there was an explosion. The bomb he was carrying exploded and he died on the spot,” said the Rab spokesperson.

Talking to The Daily Star, a junior Rab official said he was taking a shower when he saw a man with a bag walking into the premises. He also heard two of his colleagues accosting him.

“Soon, I heard a loud bang. When I looked in that direction I saw a mutilated body and my colleagues writhing in pain,” said the official, asking not to be named.

Rubel Hasan, a fish seller who was at the Hajj Camp Mosque adjacent to the barrack, said he felt the explosion shook the entire area.

The barrack is about a hundred metres from the Airport intersection. There are several tin shacks of the barracks near the boundary wall adjacent to the Hajj Camp.

The space where the officials take shower is between two tin shacks. Rab officials said they suspected that the man entered the premises by climbing the wall adjacent to the Hajj Camp.

Some worshippers who were at the Hajj Camp Mosque to say their prayers told The Daily Star that they were startled by the explosion. Later, several people came to the mosque and told them what happened inside the barrack. Some of them attempted to get out of the mosque to see what was happening, but the imam asked them to calm down.

Earlier on December 24, a female militant suspect blew herself up detonating a suicide vest as police were raiding a militant hideout, about 300 yards from the same Rab barrack. The suspect's four-year-old daughter, who was with her, survived with serious injuries.