Updated

A U.S. Patriot missile battery shot down a British Royal Air Force fighter aircraft Sunday near the Iraqi border with Kuwait. The two fliers on board were killed, the British military said.

A statement from the Royal Air Force base at Marham, in Britain, confirmed the men were dead. It did not identify them.

"They were returning from one of many successful and professionally conducted missions in Iraq, and I would like to pay tribute to their expertise and dedication," Wing Commander Mike Oldham of Britain's Marham base said in a statement.

The downing of the RAF Tornado GR4 near the Iraq-Kuwait border brings to 16 the tally of British servicemen who have died in the U.S.-led war on Iraq. The others died in the crash of a CH-46 Sea Knight helicopter a mid-air collision Saturday of two British Royal Navy helicopters. Five Americans were also killed in those incidents.

Oldham said the crew's families had been notified and an investigation was underway. The statement gave no further details.

The Tornado was returning from an operational mission early Sunday and "was engaged near the Kuwaiti border by a Patriot missile battery," the British press information center at U.S. Central Command in Qatar said in a statement.

Asked how a U.S. missile could have brought down the plane, Air Force Gen. Richard Myers, chairman of the Joint Chiefs, told ABC's This Week that "procedures and electronic means to identify friendly aircraft and to identify adversary aircraft ... broke down somewhere."

"Central Command is looking into that as we speak. Again, it's a terrible tragedy and our hearts go out to the crew members," Myers told ABC.

Lockwood noted the missile is designed to intercept everything above it from incoming ballistic missiles to low-flying cruise missiles.

"We wish to find out just as everybody else does, the U.S. as well, why this happened. And we will be carrying out a joint investigation to determine the facts so that we can eliminate this problem forever," he said.

Britain has sent some 45,000 military personnel to the Persian Gulf to join nearly 300,000 Americans deployed against Iraq. Defense Secretary Geoff Hoon said "an enormous amount of effort" had been spent on fitting the best possible protection against "friendly fire."

"But there is no single technological solution to this problem. It is about having a whole set of procedures in place. Sadly on this occasion they have not worked," he told British Broadcasting Corp. television.

RAF Group Capt. Jon Fynes said the Tornados were flying bomb strikes.

Lockwood acknowledged the bad start for the British so far in the campaign, saying it was "not one we would have chosen, I have to say, but this you must remember is high-intensity conflict. This is war and it's not training."

"We will continue to do our job and see it to its finish," he said.