The Kuwaiti Interior Ministry has said an Iraqi ship has opened fire on two Kuwaiti coastguard patrol boats, causing them to collide.

The presence of US troops may have escalated tensions

"When the two coastguard boats were on a routine patrol in the northern region near Warba island, there was an Iraqi vessel in the area which opened fire on them," the official Kuna news agency reported.

A member of the coastguard was hurt when two boats collided after the attack, the agency added.

Kuna's Faris Glubb told the BBC that the incident was probably the irresponsible action of an individual Iraqi commander, and is unlikely to be pursued by either side.

There has been no confirmation of the attack from Baghdad, and United Nations officials monitoring the two countries' border said they had no knowledge of the incident.

Piracy accusations

US officials on Tuesday said they were looking into the incident.

Similar incidents have happened before but they have been infrequent in recent years.

The BBC's Paul Wood in Cairo says it may be one sign of the increasing tensions surrounding the US military build-up in the region.

Kuwait and Iraq have had no diplomatic relations since the Gulf War in 1991, in which US-led forces liberated Kuwait from Iraqi occupation.

Iraq often accuses Kuwait of "piracy" against its shipping, while Kuwait says it has intercepted Iraqi boats carrying goods in violation of a UN embargo.

Warba is a small island consisting mainly of mud flats just two kilometres off the Iraqi coast, and one of nine in the Gulf with Kuwaiti sovereignty.