COPENHAGEN, Denmark (AP) _ A Danish trawler was pulled backward and almost dragged under the water when an unidentified submarine got caught in its net, the navy said today.

Skipper Michael Hansen and his helper, Kjeld Dideriksen, were fishing Tuesday in the Baltic Sea, 20 miles southeast of the Danish island of Bornholm.

Suddenly the trawler, Christina-Michelle, stopped dead in the water, and then began to run backward. The trawler was towed partially under water.

Hansen let go of his nets when he realized what was happening.

The sub did not surface, the navy said.

The Danish navy spotted what was believed to be the sub when it surfaced several hours later and identified it as a Soviet-built vessel, said Commander Senior Grade Ole Bratting of the Bornholm district marine command.

Bratting said the sub flew no flag and had no markings, which is typical of Soviet vessels operating in the Baltic.

The sub apparently was taking part in an anti-submarine warfare exercise held by the East German navy in the western Baltic at the time of the trawler episode, Bratting said.

The navy said the incident was a common occurrence in Baltic Sea waters.