The BBC's Tom Carver: "Saddam Hussein still controls the initiative"

An Iraqi military communique issued in Baghdad said four soldiers died and seven were wounded when "enemy planes" fired missiles at an Iraqi anti-aircraft position just north of Mosul.

The Pentagon and the UK's Ministry of Defence have confirmed that the missiles were fired, but say this was in retaliation for an attack from the anti-aircraft base.

US President Bill Clinton defended the action as a legitimate act of self defence.

The Iraqi communique, reported by the official INA news agency said: "Enemy planes flying out of Turkey violated Iraqi airspace at 13:37 local time (1037 GMT) and approached anti-aircraft positions before firing missiles on one of the positions".

'Self defence'

Pentagon spokesman Col Richard Bridges said US warplanes fired on an Iraqi target in response to "an act of aggression" while US fighter planes were enforcing the no-fly zone in northern Iraq.

President Clinton: "We will continue to enforce no-fly zones"

"It was an act of self defence," he added.

The official Iraqi news agency says a western military aircraft was probably shot down. But the US, who earlier confirmed its planes had returned safely to base in Turkey, denied the report.

President Bill Clinton, speaking shortly after the attack, said that the no-fly zones were an important part of the US's "containment strategy" against the Iraqi government.

Caroline Wyatt: "War of words"

He said the two zones, one in the north and a second in the south stretching from the Baghdad suburbs to the border with Kuwait, were there to prevent aggression by Baghdad.

"We will continue to enforce the no-fly zones," the president pledged.

A spokesman for the UK Ministry of Defence said: "There are reports of US aircraft coming under attack from surface-to-air missiles in the north of Iraq.

"Under the rules of engagement, the (planes) are allowed to defend themselves."

He added that no UK planes were involved in the incident.

The incident follows a warning to Iraq by the US and the UK that they will not tolerate any interference with their aircraft patrolling the no-fly zones in the north and south of the country.

The warning came after the Iraqi Vice-President, Taha Yassin Ramadan, said Iraq did not recognise the no-fly zones and would fire on any planes violating its airspace.

Our correspondent in Baghdad says Iraq is keen to portray itself as the victim of Western aggression, and thereby win diplomatic support.