The Soviet Union is not seriously interested in pulling out of Afghanistan, and recent reports of a withdrawal timetable are aimed mainly at undermining the confidence of Afghan guerrillas and their U.S. supporters, according to U.S. government analysts.

Their assessment of current Soviet diplomacy involving the six-year Afghan conflict is contained in a cable sent this month by the State Department to all U.S. embassies. A U.S. official said it was sent because of concern that other nations may misinterpret Washington's show of interest in Soviet hints at willingness to withdraw.

The cable notes that the United States has not seen any Soviet withdrawal timetable, nor has Pakistan or the United Nations, which sponsors indirect talks between Pakistan and Afghanistan.

Reports that Afghan Foreign Minister Shah Mohammed Dost had shown such a plan to Diego Cordovez, the U.N. undersecretary general for political affairs, at the last such indirect talks in Geneva Dec. 16-19 were not true, the cable reportedly says.

Since President Reagan and Soviet leader Mikhail Gorbachev met there last November, reports have proliferated that Moscow might be rethinking its involvement in Afghanistan and be ready to seek a negotiated settlement.

Such speculation was heightened after the Dec. 16-19 talks between Pakistan and the Soviet-backed Kabul government. There, the Afghans said they had details of a Soviet withdrawal plan in hand but refused to discuss it unless the Pakistanis agreed to direct negotiations.

Even some high-level U.S. officials first interpreted the Afghans' disclosure as another indication that Gorbachev might be seriously considering withdrawal of the estimated 118,000 Soviet troops from Afghanistan.

In addition, the Afghan government has recently brought into its ranks a dozen noncommunist figures and hinted that opposition leaders may be allowed to join.

U.S. analysts said they think, however, that these moves are simply part of a Soviet and Afghan campaign to gain Pakistan's diplomatic recognition of the Kabul government and strengthen its international standing. Such a development also is likely to provoke tension between Pakistan and Afghan resistance groups based there.

"We see very little indication of a Soviet interest to get out," one U.S. intelligence analyst said.

Elie D. Krakowski, special assistant to Assistant Defense Secretary Richard N. Perle, presented a more complete public version of this U.S. assessment of Soviet and Afghan maneuvers Thursday at a discussion sponsored by the conservative Heritage Foundation.

In a Pentagon-approved statement, Krakowski said that, despite hints of new Soviet flexibility, no evidence has been found that Moscow has changed its principal demand for an end to outside support for the Afghan resistance before it considers withdrawal.

"It is significant that all the 'hints' of a modification in the Soviet position do not even claim that this crucial condition is about to be modified," he said. "Moscow is in fact saying that the only way it will ever withdraw is when the Afghan resistance has been eliminated."

Krakowski charged that Moscow and Kabul, in attempting to lure Pakistan into direct negotiations, are trying to obtain legitimacy for the Afghan government that it "has been unable otherwise to achieve."

"The Soviets are keenly aware that the very mention of the possibility of a deal over the heads of the Afghan resistance sends tremors through the ranks" of the Afghan guerrillas, Krakoswki said.

More important, he charged, the Soviet and Afghan moves are an attempt "to create anxiety and distrust within the Afghan resistance and the Pakistani government about the U.S.'s motives and reliability."