US and NATO officials said the air war against Yugoslavia would continue for the present, despite Belgrade's acceptance Thursday of NATO's basic demands for ending its bombardment of the country.

President Clinton and British Prime Minister Blair called “positive” and “encouraging,” the Serb leadership's acceptance of a document presented by Finnish President Martti Ahtisaari and Russian envoy Viktor Chernomyrdin, but insisted that the bombing would continue until Belgrade began a major and verifiable withdrawal of its military and police forces from Kosovo.

Interviewed Thursday on the PBS Television evening news program, US Defense Secretary William Cohen said he expected that within several days NATO military leaders would meet with their counterparts in Belgrade to discuss details for implementing the withdrawal of Serb troops and the occupation of Kosovo by a NATO-dominated military force. Cohen added, however, that until a Serb withdrawal begins, “We will continue inflicting serious and substantial damage on Milosevic's forces.”

Ahtisaari and Chernomyrdin arrived in Belgrade Wednesday and presented Yugoslav President Milosevic with a “non-negotiable” proposal for ending the NATO air war, which in the course of 72 days has inflicted massive damage on the country's economic and social infrastructure and caused thousands of civilian casualties. Even as they met with Milosevic, NATO bombs and missiles struck television facilities and bridges in various parts of Serbia.

To underscore the damage already inflicted and, by implication, warn of more to come, a NATO military spokesman on Thursday provided the alliance's first estimates of Serb military casualties since the war began last March. He said at least 5,000 Serb troops had been killed and 10,000 wounded, figures substantially higher than those released by Belgrade.

The proposal brought by Ahtisaari and Chernomyrdin had been hammered out in advance and vetted by US Assistant Secretary of State Strobe Talbott.

A key factor in Milosevic's decision to accept the NATO ultimatum, containing essentially the same demands that he had rejected at the Rambouillet meetings last February and March, was the role of Chernomyrdin and the Russian government. Russia dropped all pretense of opposition to NATO's terms, as well as its previous insistence that NATO suspend its bombing prior to a Serb withdrawal from Kosovo.

As George Jahn of the Associated Press noted: “Russia was the key. After more than two months of NATO bombing Moscow abandoned its position as an outspoken advocate of Yugoslavia. The Russians clearly did not want to risk their economic and other ties with the West to line up with Europe's renegade nation.

“‘It is necessary for the Yugoslav leadership to accept this document,' Valentin Sergeyev, a spokesman for Russian envoy Viktor Chernomyrdin, said today in language that could not have been a plainer signal to Milosevic.”

Milosevic called a meeting of the Serbian National Assembly for Thursday morning in order to get its approval of the NATO plan prior to the Yugoslav government giving its official support. The Serb parliament voted 136 to 74 to accept the so-called peace plan, in a session that, according to some delegates, saw heated arguments and near fist-fights among the delegates. The ultra-nationalist Radical Party, the second largest after Milosevic's party, voted against the plan and walked out of the chamber in protest.

Following the vote by the Serb parliament, the federal Yugoslav government announced its support for the NATO plan.

The major terms of the document, according to a translation released by the Associated Press, include:

* The rapid withdrawal of all Serb military, police and para-military forces from Kosovo. A period of seven days is proposed for the process to be completed.

* Occupation of Kosovo by a military force, nominally under United Nations auspices, but with an “essential” NATO participation. NATO officials are preparing to deploy 50,000 troops.

* Return of Kosovar refugees and the establishment of an “interim” administration, under the auspices of the UN Security Council. The agreement gives this administration sweeping powers to set up new institutions of government, with no apparent role for the Yugoslav government in Belgrade.

* Once the Serb withdrawal has been completed and the NATO-led military force has been installed, Belgrade is to be permitted to bring a token force of “hundreds, not thousands” of military and civilian personnel into Kosovo. Their role is limited to “liaison with the international civilian mission and international security presence, marking mine fields, maintaining a presence at places of Serb heritage, maintaining a presence at key border crossings.” These duties are to be carried out “under the supervision of the international security presence”.

* The agreement calls for autonomy for Kosovo, while recognizing “the principles of sovereignty and territorial integrity of the Federal Republic of Yugoslavia and other states in the region”.

* It calls for the “demilitarization” of the Kosovo Liberation Army.

Belgrade is emphasizing the formal role of the United Nations, rather than NATO, in overseeing the occupation of Kosovo, a largely symbolic concession agreed to by the US and Britain. In essence, the agreement provides for the establishment of a US-NATO protectorate over the province.