A suicide bomber detonated his explosives among a crowd of Yemeni police cadets as they were leaving their academy Wednesday, killing at least 10 of them, according to security officials.

The Interior Ministry said al-Qaeda was behind the bombing, which struck in the capital Sanaa. Security officials said 20 cadets were wounded, including three critically. They were leaving the Police Academy for a weekend with families when the bomber hit at the facility's southern gate.

The Interior Ministry identified the attacker as Mohamed Nasher al-Uthy from the province of Amran, about 70 kilometres northwest of Sanaa. It said he lost the lower part of his body in the blast and died of his wounds minutes later. No other details were provided.

There was no immediate claim of responsibility for the blast, but al-Qaeda's Yemen branch frequently targets security forces.

Twelve suspects have been arrested in connection with Wednesday's attack, according to security officials.

The capital was on high alert after the attack, with security forces setting up checkpoints around the city and searching cars. Security was also beefed up around embassies.

The attack came after the army last month recaptured several militant-held towns in the country's south, following a monthslong campaign to retake territory the militants seized during last year's political turmoil that swept the country.

Al-Qaeda in the Arabian Peninsula, considered the global terror movement's most dangerous offshoot, has struck back against the military's offensive with deadly attacks in the south and a May 21 bombing at a parade ground in Sanaa that killed 96 Yemeni soldiers.

Security officials said 55 people have been arrested in connection with that attack, among them al-Qaeda militants accused of plotting to attack the U.S. Embassy.

Last week, Yemeni state TV aired a number of the detainees' purported confessions, with one of the accused saying he had orders to carry out an attack against the U.S. Embassy and other foreign embassies. He did not elaborate.

Earlier Wednesday, the government announced that two al-Qaeda militants who tunneled out of a prison last month were re-arrested in a southern province. An Interior Ministry statement said one of the two, Nasser Ismail Ahmed Muttahar, was detained for taking part in an attack on the U.S. Embassy in Sanaa in 2008.

The attack on the embassy's gate, carried out by gunmen and vehicles packed with explosives, killed 19 people including an 18-year-old American woman and six militants. None of those killed or wounded were U.S. diplomats or embassy employees. It was the deadliest assault on a U.S. embassy in a decade.

The two militants who had escaped prison were captured in al-Dhali province on Tuesday. The ministry statement said they were among five militants who escaped from a prison in the western province of Hodeida on June 26.