http://news.bbc.co.uk/1/hi/uk/2877349.stm RAF Tornado downed by US missile
An RAF Tornado and its crew are missing after being downed by a US Patriot missile close to the Kuwaiti border.
A search for survivors is under way, as is an investigation into how the accident happened.
Air Marshal Brian Burridge, commander of British troops in the Gulf, said the Tornado had been hit "obviously by mistake" as it returned from a mission over Iraq.
William Farish, the US ambassador to Britain, told the BBC the loss of the plane was "absolutely terrible".
It comes after two helicopter crashes within the last three days led to the deaths of 19 coalition troops, including 14 Britons.
The lost Tornado was from RAF Marham, the Norfolk airbase that has often provided planes for no-fly zone patrols before the invasion began.
Three ITV news crew are also missing and feared dead, after coming under what their injured colleague claims was "friendly fire".
After the RAF plane went missing, Group Captain Al Lockwood, chief spokesman for the British forces, said: "This is a tragedy and we are taking rapid steps to find out the reason and to ensure that there is no repetition."
Air Marshall Burridge told the BBC's Breakfast with Frost programme: "This is a sad moment but we will put it behind us as quickly as we can in a military sense and carry on to our objective."
He said a military coalition is "probably the most intimate alliance you can imagine" and that there was a "bond of trust" between the UK and US forces.
In a statement Downing Street said the prime minister knew about the accident, adding that he understands it is "an extremely difficult time for those involved, their families and colleagues of the crew who are missing".
The US ambassador said: "Friendly fire is something we have lived with for ages throughout wars, but to have it happen in a way like this is very sad."
Tory leader Iain Duncan Smith said: "I am afraid that it is the nature of warfare and you try to minimise this, but it is a tragedy nonetheless for the families."
The loss of the Tornado - which normally carries a two-man crew - came after two Royal Navy Sea King helicopters from the Ark Royal collided over the Gulf on Saturday, with the loss of all seven crew members - six British and one American.
A memorial service has been held on board the aircraft carrier for those killed. So far, only one body has been recovered.
On Friday an American CH-46 Sea Knight crashed over the Kuwaiti desert killing eight British and four American service personnel.
The number of accidental deaths amounted to a difficult start to the campaign "and not an ideal one for the UK", Captain Lockwood said.
"It's been tragic and there's been a great deal of sorrow for those concerned and their families and friends."
Coalition leaders are anxious to limit the chances of further accidental deaths and have taken measures against the dangers of friendly fire.
UK Defence Secretary Geoff Hoon, who sent his sympathies to the families who had lost loved ones, said there were a set of procedures in place to defend British and coalition forces.
"Sadly on this occasion they have not worked and we are conducting urgent reviews, both of the operation of missile batteries as well as of our own aircraft to ensure that this cannot happen again," he told the BBC's Politics Show.
US Marines' air controllers have been attached to UK forces to co-ordinate strikes against Iraqi positions.
British armoured vehicles have also been fitted with identification panels and beacons, which can be switched on if they fear they are at risk from attack.
As US-led military action against Iraq continues, forces are still encountering pockets of resistance as they advance towards Baghdad.
Clashes are continuing near the holy town of Najaf in the desert just 160 kilometres (100 miles) south of the Iraqi capital.
American B-52s bombers again took off from RAF Fairford on Sunday morning. The two aircraft are believed to be heading for Baghdad.