The Soviet Union today accused President Carter of lying about Afghanistan during his European tour and blamed him for preventing a political settlement of the crisis.

In the harshest attack so far on recent U.S. hints of willingness to discuss ways to end Moscow's military intervention, the official Tass press agency in an authoritative unsigned commentary said Carter "once again spread deliberately slanderous fabrications about a mythical Soviet menace" to reach Arabian seaports.

"As for the 'versions' spread by the president, it is either a profound and dangerous mistake or more likely than not, a deliberate lie."

The Communist Party daily, Pravda, in a separate commentary widened the attack, saying U.S. suggestions about finding a government acceptable to the Afghans "is an overt appeal to enemies to carry on subversive actions against the present government!"

The continuing barrage seems to reduce almost to zero the possibility that Moscow is interested in engaging in serious talks with the Western allies or Washington about a settlement.

Veteran observers here say they see the partial Soviet troop withdrawal announced Sunday as a Kremlin ploy to bolster its image during the coming Moscow Olympics and the summit visit of West German Chancellor Helmet Schmidt. They add that the move also may eventually be used by Moscow as potential justification for later expanding its involvement.

The Tass commentary strongly hinted of this.

"If Washington and the accomplices of American imperialism persist in implementing their plans of making Aghanistan a springboard for aggression on [our] southern frontiers, they would do well to bear in mind that the Soviet Union, its friends and allies, have means to give a fitting rebuff."

The Soviet insist that the only acceptable frame-work for a settlement is the May 14 proposal by Afghan President Babrak Karmal's Marxist regime, which wants world diplomatic recognition, an end to the Moslem tribal rebellion, and regional peace talks with Iran and Pakistan, where more than a million Afghan refugees live.

The sharpness of the Soviet denunciations of Carter are also seen here as motivated by Moscow's acute awareness that the Marxists maintain power in Afghanistan only because of Soviet forces. Carter's suggestion of an alternative government acceptable to the mutinous populace exposes Moscow's vulnerability on this basic issue.

In its commentary, titled "Facts Against Lies," Tass assailed the administration, saying Carter's European comments "show that anti-Sovietism, hostility to detente, continues as the foundation of the policy of the present Washington administration."

[In Washington, State Department officials said they did not think the latest Soviet statement constituted a final rebuff, Reuter reported. "They're doing what we're doing -- taking a hard public line," an official said. "It's the damndest sort of dialogue but there is a dialogue," he said.]