A British soldier was killed in combat in southern Iraq on Monday, the first British combat death since the war began, the Ministry of Defense said.

The soldier, whose name was not made public, was killed near Az Zubayr in southern Iraq, the ministry said. A spokeswoman declined to provide further details, but said the soldier's family had been notified.

Sixteen other British servicemen have died in the Persian Gulf, in two helicopter accidents and the downing of a British jet by friendly fire from a U.S. missile battery. Two others were reported missing Sunday after their convoy was attacked in southern Iraq.

In the southern Iraqi navy port of Az Zubayr, which the coalition claimed Sunday, a U.S. Marine patrol reported being fired on Monday from a stand of trees; Marines responded with tanks and artillery fire. It was not clear who fired on the patrol or if the firefight was related to the British death.

British officials have rejected suggestions that continued Iraqi resistance and coalition casualties had knocked war plans off balance, or undermined public support.

"I think that within three days of real military operations beginning, the idea that somehow people are losing confidence or heart is nonsense," Defense Secretary Geoff Hoon told a news conference.

"This is a difficult demanding, complex, sophisticated military operation. It is not going to be over in a matter of days," Hoon added.

The Ministry of Defense said the two missing soldiers came under attack on Sunday, but declined to identify the location or the units involved for safety and operational reasons.

At U.S. Central Command in Qatar, Group Capt. Al Lockwood, a spokesman for British forces in the Gulf, said British vehicles were attacked by regular army Iraqi forces and the occupants of one Land Rover were missing.