March 17, 1984

An American diplomat was kidnapped at gunpoint here today by a carload of unidentified gunmen outside his apartment building as he was leaving for work. No group immediately claimed responsibility. Witnesses and American officials said the diplomat, William F. Buckley, first secretary in the United States Embassy's political section, was forced out of his car, a beige Honda, at gunpoint at about 7:30 this morning and was bundled into the abductors' white Renault. ''The whole thing took three minutes,'' said Mohammed Moussa, the superintendent of the apartment building where Mr. Buckley lived. American officials later received reports that the Renault had been seen speeding south down the coastal highway.

Mayor Koch announced yesterday that New York City had rejected a revision of its rent-stabilization code that tenant groups said would have substantially weakened their rights. The Mayor said tenants and landlords had been unable to cooperate in deciding how the code, a highly technical 75-page set of rules and regulations, should be altered. ''It's a victory for reasonableness and common sense,'' Mr. Koch said in announcing the decision at City Hall. ''I think it's fairer.''

Edwin Meese 3d said today that critics of his nomination to be Attorney General were making ''false and misleading statements.'' He added, ''I have engaged in no improper conduct.'' In a statement Mr. Meese, President Reagan's counselor, sent the Senate Meese statement, page 10. Judiciary Committee, which is considering his nomination, he urged his critics to wait until he could explain his activities when he returns, probably next week, to testify before the committee again.

Congressional officials said today that President Reagan agreed to reduce his military budget request only after Senate Republican leaders committed themselves to making no further cuts. The reduction that Mr. Reagan and Defense Secretary Caspar W. Weinberger accepted Thursday as part of an attempt to reduce the Federal budget deficits came to $57 billion over three years. This would leave the military budget at $1,004 billion over the next three years, as against the $1,061 billion initially sought by the Administration. A spokesman for the Office of Management and Budget said that if the compromise was adopted by Congress, it would set the military budget at $299 billion in the fiscal year 1985, a 7.8 percent increase over the 1984 level, after making up for the effects of inflation.

Mozambique and South Africa, bitter ideological adversaries, signed a nonaggression treaty today, promising to withhold support for one another's internal foes. It was the first such pact between South Africa and a black-ruled African country. The agreement was signed by President Samora M. Machel of Mozambique and Prime Minister P. W. Botha of South Africa in the humid no-man's land between their two countries, under a white pavilion in a makeshift city of military tents by the Komati River. It represented a major diplomatic victory for South Africa in its campaign against the African National Congress, and an acknowledgment by Mozambique of Pretoria's military and economic ability to impose its will. Setback for Rebels It also meant a severe setback for the African National Congress, the most prominent of the exiled groups fighting South Africa's policies of apartheid, or racial separation, from bases in Mozambique, and for the Mozambique National Resistance, a South African- supported group fighting President Machel's avowedly Marxist regime.