US President Barack Obama has for the first time publicly accused an offshoot of al-Qaeda over the alleged Christmas Day bomb plot to blow up a US plane. He said it appeared Yemen-based al-Qaeda in the Arabian Peninsula had armed and trained the accused, 23-year-old Nigerian Umar Farouk Abdulmutallab. The group admitted responsibility in an internet statement last week. Mr Obama has already condemned lapses that allowed the accused, who was on a terror database, to board the jet. In his weekly radio and video address posted on the White House website early on Saturday, Mr Obama said more details of the alleged plot were becoming clear. "We know that [Mr Abdulmutallab] travelled to Yemen, a country grappling with crushing poverty and deadly insurgencies," said Mr Obama, who is on holiday in Hawaii. "It appears that he joined an affiliate of al-Qaeda, and that this group, al-Qaeda in the Arabian Peninsula, trained him, equipped him with those explosives and directed him to attack that plane headed for America." US officials have not until now publicly accused al-Qaeda over the incident on Flight 253 from Amsterdam to Detroit. Mr Obama has come under heavy criticism from Republicans, who accuse him of not doing enough to prevent attacks on the US. Some Democrats, too, have joined the clamour for an overhaul of intelligence procedures. The US president - who last week ordered two security reviews - used much of his latest address to outline his administration's measures to keep America safe. He said these included withdrawing troops from Iraq, boosting troop levels in Afghanistan and targeting militants in Yemen, where the suspect spent time before the attack. "All those involved in the attempted act of terrorism on Christmas must know you too will be held to account," he said. The US Congress, meanwhile, is preparing hearings to question intelligence officials on security failings that allowed a man whom US officials had been warned about, and who had a valid US travel visa, to allegedly smuggle explosives on to a transatlantic jet. Mr Abdulmutallab, now in US custody, is accused of trying to detonate explosives strapped to his body as the plane, with nearly 300 people on board, prepared to land. The mid-air drama on 25 December has spawned a worldwide aviation security review. British Prime Minister Gordon Brown warned on Friday that rising Islamist militancy had turned Yemen into "an incubator for terrorism". He announced an international conference in London in late January to discuss the danger. Source: BBC