OSLO, Norway (AP) _ A Greenpeace ship used in protests against commercial whaling in Norwegian waters was ordered Thursday to remain under port arrest for the rest of this month.

The coast guard seized the Sirius on Monday after a North Sea confrontation in which the activists claimed that whalers aboard the trawler Kato shot at them with a rifle.

The activists had been trying to prevent the Kato from killing its quota of minke whales in an area about 115 miles off Norway's southwestern coast.

Police confirmed that a rubber boat used by Greenpeace was probably hit by bullets, and said they will question the whalers when the Kato returns to port. The hunters said they were shooting at a wounded whale.

Norway resumed its commercial whale hunts in 1993, saying the minke whales it hunts are plentiful. Norway is not bound by a 1986 commercial whaling ban imposed by the International Whaling Commission because it rejected the ruling as allowed by the group's charter.

Police ordered the Sirius brought to port after Greenpeace activists in rubber boats repeatedly refused to withdraw from a 500-yard security zone around the Kato.

The Sirius is a ``mother ship'' used by the activists. They lived on board and launched their rubber boats from it, because the whalers were too far out to sea to reach in small boats.

It was towed to the port of Stavanger, about 220 miles southwest of Oslo. There, a preliminary court ruled that the ship held until the hunt ends Aug. 1.

On Tuesday, Greenpeace said it would go to court to fight fines imposed on its activists by the police.

The Sirius' captain was handed a $3,800 fine and six other activists were ordered to pay fines ranging from $1,900-$2,280 each for hampering the whale hunt.

Minke are the smallest of the baleen whales at about 30 feet. Whalers have so far killed about 500 of this year's quota of 753 whales.