OSTEND, Belgium (AP) _ The outlawed Irish Republican Army on Saturday claimed responsibility for killing a British soldier in this North Sea port and urged civilians and families not to travel with British troops.

Belgian police, meanwhile, continued to search for two men who gunned down Warrant Officer 1st Class Richard Michael Heakin, 38, of the Royal Regiment of Wales' First Battalion, on Friday night.

The British Defense Ministry said Heakin was going home on leave from his base at Moenchen Gladbach, West Germany, and planned to take a ferry Friday night to Dover, England.

Heakin was attacked as he waited in his car at a traffic light an hour before the ferry's departure. Two men in their 20s approached his car, one opened fire and both men fled on foot toward a city park, a Belgian police official said. He spoke on condition of anonymity.

Officials said Heakin, who was married and had a 9-year-old son and a 7- year-old daughter, died at the scene.

The IRA claim for the Friday night attack came in a statement to the news media in Britain.

The outlawed group wants to drive the British from Northern Ireland and unite the mostly Protestant province with the overwhelmingly Catholic Irish Republic.

''We reiterate our call to civilians and the families of soldiers not to travel with Crown Forces personnel,'' the statement said.

Heakin was in civilian clothes but drove a British-made Vauxhall with British Army of the Rhine tags.

After the shooting, police took witnesses to the ferry dock to try to identify the assailants from among passengers on two ferries to Dover. They were not spotted.

The IRA intensified its campaign against British security forces on Aug. 1 when it bombed a barracks in north London, killing one soldier and injuring nine. Attacks last week in Northern Ireland killed five people.

In March 1987, the IRA launched its first attack on British servicemen on the European continent in about a decade, setting off a bomb near a British officers' mess at Rheindahlen, West Germany. Thirty-one people were injured.