LONDON (AP) _ Amnesty International said today that Libya has assassinated 25 political opponents in 37 attacks outside the country during the past seven years.

The London-based human rights organization appealed to Libya's leader, Col. Moammar Gadhafi, to renounce the policy of ''physical liquidation.''

The appeal, issued in a statement, followed the June 26 shooting death in Rome of Yusuf Khraybish, a member of the rebel National Front for the Salvation of Libya.

It was the third attack on a Libyan exile this year under a liquidation policy begun in March 1980, Amnesty International said.

Most of the attacks have been in Italy, Greece and Britain, but others were in Austria, Cyprus, Egypt, West Germany, Lebanon and the United States, the organization said.

Amnesty International said most of the victims were active opponents of the Libyan government, but others were simply suspected of being sympathetic to the opposition. Among them were businessmen, students, former diplomats and other government officials, the group said.

In most cases, the attackers have been young Libyans who often described themselves as members of Gadhafi's Revolutionary Committees. Most victims were shot at point-blank range in daylight in public places, but others were strangled or stabbed in their homes.

Libyan authorities have claimed responsibility for some attacks on exiles, Amnesty International said.

The United States closed the Libyan People's Bureau, or embassy, in Washington in 1980, citing Libyan misconduct and provocations.

Britain severed diplomatic relations with Libya after a policewoman was killed in April 1984 when shots were fired from inside the Libyan Embassy in London on a crowd of Libyan students demonstrating outside the building.