Amnesty International yesterday called for an international moratorium on executions and appealed to U.N. Secretary General Kurt Waldheim to convene an emergency meeting of the Security Council to halt the resurgence of political killings in the world.

"We have witnessed an extraordinary seven days of murder in cold blood," Thomas Hammarberg, chairman of the organization's executive committee, said in a statement. He said persons in 12 countries have ither been sentenced to death, executed or assassinated.

Among the dead are the former prime ministers of Iran and Pakistan, Amir Abbas Hoveyda and Zulfiqar Ali Bhutto, 10 political prisoners in Mozambique, five blacks in South Africa including Solomon Mahlangu, five Nigerians, and victims of assassinations in England, Guatemala and El Salvador.

Imminent executions of both political prisoners and criminal offenders are feared in Iran, Pakistan, the United States, the Soviet Union, Trinidad and Cambodia. The execution of American John Louis Evans in Alabama was stayed Friday five hours before he was to go to the electric chair. A Soviet prisoner was reported Saturday to have been sentenced to die after pleading guilty to a series of attacks on women in Moscow.

"We are urging the U.N. Security Council to take emergency action for two reasons," Hammarberg said. "We want the death toll to stop. We unequivocally condemn each death sentence and each killing as a denial of the purposes of the U.N. charter and a violation of the human rights and fundamental freedoms proclaimed in the universal declaration of human rights."