DUBAI, UNITED ARAB EMIRATES, NOV. 20 -- Iraqi jets hit a tugboat today in the Persian Gulf near Iran's Kharg Island oil terminal, killing a crewman and wounding five.

Shipping sources in the gulf said the salvage tug Salviva was hit by an Exocet missile. Last week, Iraqi warplanes attacked another tug, killing three crewmen.

The tugs, based in the United Arab Emirates port of Sharjah, are used to fight fires aboard supertankers, as well as to help the giant ships to manuever.

In apparent acknowledgment of the raid, Iraq said its jets hit a "large naval target" in the gulf this morning. Iraqi pilots reportedly often fire missiles at great distances and can distinguish their targets only as a radar blip.

Two Belgian and two Dutch mine sweepers sailed into the gulf today, joining U.S., British, French and Italian ships already in the waterway. Belgian defense officials said Britain asked for the mine sweepers' help after finding mines off Qatar yesterday. The British destroyer York will protect the ships.

{U.S. Navy forces destroyed two suspected Iranian mines in the past two days, about six miles from the area near Farsi Island where the tanker Bridgeton struck a mine in July, Pentagon officials said.

{The officials said they did not know whether the mines were planted recently or were left from the mines sown in July. They also said former defense secretary Caspar W. Weinberger had authorized deployment of the first naval reserve ship, the guided-missile frigate USS John A. Moore, to the gulf. The crew will include primarily active-duty sailors, with some volunteer reservists.}

Also today, Iranian parliamentary speaker Ali Akbar Hashemi Rafsanjani said Tehran is negotiating a new defense agreement with the Soviet Union, according to the Japanese daily Asahi Shimbun. The paper quoted Rafsanjani in an interview as saying he had accepted a Soviet invitation to visit Moscow soon for talks, but that "little progress has so far been made."

However, according to the Soviet armed forces newspaper, The Red Star, Soviet and Iranian ships in the gulf recently had their first confrontation. United Press International reported from Moscow that the paper said today an Iranian frigate had pointed its guns at a Soviet ship and made a hostile pass at a convoy under Soviet naval escort.

The front-page report did not say exactly where or when the confrontation took place but observers said it was likely to have occurred Wednesday or last night when a convoy escorted by the destroyer Stoiky was navigating through heavily mined waters. The newspaper said an Iranian frigate trained its guns on a tanker, the Argun, and began making a high-speed approach.

It quoted the captain of the Stoiky, Mikhail Volk, as saying the convoy was in international waters at the time of the attack and despite a radio warning to change course, the frigate continued approaching.

The newspaper did not say if shots were fired.