The longest day: bombs kill 20 in Turkey as 12 die in helicopter collision in Iraq

Yesterday was one of the worst days for President George Bush and his administration since he launched his "war on terror" and invaded Iraq. As bombs blamed on al-Qa'ida devastated synagogues in Turkey's largest city, killing at least 20, the American death toll in Iraq rose well above 400 following a collision between two helicopters above Mosul.

A US officer on the scene said one of the helicopters had been hit in the tail by a rocket-propelled grenade before crashing into the other. "I saw two helicopters," said a local man, Mohammad Badran. One was flying low and was on fire. The other was higher up. The first one climbed and hit the higher one." An official statement said 12 soldiers died and nine were hurt, but there was no word of possible casualties on the ground.

The US forged ahead yesterday with a plan formally to end its occupation of Iraq - though not its military presence - next June, but the announcement was overshadowed by multiple signs of insecurity, including the death of a soldier on patrol in northern Baghdad, an explosion that derailed a train near Tikrit and another blast in the centre of the capital.

The collision between two Black Hawk helicopters took the American death toll since the war began on 20 March to 412. And as an aircraft carrying the remains of 18 Italians killed in a suicide bombing landed in Rome, a 19th died of injuries sustained when the Carabinieri headquarters in Nasiriyah were attacked on Wednesday.

The steady loss of life in Iraq, and world condemnation of the synagogue bombings in Istanbul, highlighted an uncomfortable fact for Mr Bush as he prepared for a state visit to Britain: neither of his two prime adversaries, Saddam Hussein and Osama bin Laden, has been captured or killed, and their followers retain the ability to strike back.

It emerged yesterday that British security forces - including the police, the Army, MI5 and MI6 - have been put on the second-highest state of alert after intelligence emerged of a possible al-Qa'ida attack in Britain. The Home Office refused to confirm the "severe general" alert had been issued. The confidential alert follows warnings about attack plans being drafted by allies of al-Qa'ida in north Africa. Though the warning is not thought to be linked to Mr Bush's presence, it will complicate security for the President.

In Baghdad yesterday, the American-appointed Iraqi Governing Council said the US occupation would end in seven months, after the selection of an "independent and sovereign" transitional government. The details were made public by the council's leader, Jalal Talabani, following a six-hour meeting between the council and America's chief administrator in Iraq, Paul Bremer, who has just had emergency talks in Washington.

The move represents a shift in the policy of the Bush administration. It had previously insisted that Iraq should first have a new constitution and elections - both difficult to accomplish, given the political divisions within Iraq and the guerrilla war being waged.