MOSCOW, AUG. 7 -- The Soviet Union said today that it has some reservations about a U.S.-led economic blockade of Iraq but will faithfully carry out sanctions ordered by the United Nations against the Baghdad regime for its invasion of Kuwait.

In an interview with the government newspaper Izvestia, Deputy Foreign Minister Alexander Belonogov said Moscow had sent two messages to Iraqi President Saddam Hussein calling for a full withdrawal of Iraqi troops from Kuwait. But he said that the Iraqi leader had failed to "soften his position" in a way satisfactory to the Kremlin.

The Foreign Ministry announced meanwhile that two Soviet vessels -- a medium-size anti-submarine vessel and a command ship -- were sailing toward the Persian Gulf from the Indian Ocean. But he insisted that this was a "usual, normal" measure in view of the tension in the gulf area and was not intended to signal a reinforcement of the Soviet naval presence in the region.

Since Iraq invaded Kuwait last Thursday, Soviet commentators have kept up a steady barrage of criticism against Saddam despite traditionally close ties between Moscow and Baghdad. At the same time, the Kremlin has attempted to play a mediating role, keeping open its lines of communication to the Iraqis in addition to consulting regularly with Western nations.

"The Soviet Union's negative attitude to Iraq's invasion of Kuwait does not mean that we are not prepared to exert every effort to find an appropriate way out of the crisis by rendering every assistance to the parties involved in the Iraq-Kuwait conflict," a commentator with the Communist Party newspaper Pravda wrote.

Belonogov, who has been handling day-to-day diplomatic developments, told Izvestia that the U.S. insistence on draconian sanctions against Iraq had revealed the first difference of approach between Moscow and Washington on the handling of the crisis. He said that the Kremlin would have preferred a more "moderate line," keeping sanctions in reserve for a later date, but bowed to the majority view in the Security Council.

"Taking these measures, we are cutting through the living ties that have linked us to Baghdad for decades," said Belonogov, who met today with U.S. Ambassador Jack Matlock. "Nevertheless the Soviet Union will undeviatingly observe the Security Council resolution."

The Soviet condemnation of the invasion and the decision to cut arms supplies to Iraq have already led to a sharp deterioration of relations between Baghdad and Moscow. Soviet officials have noted that the Iraqi newspaper Al-Iraq on Sunday published a vehemently anti-Soviet commentary that is being viewed here as a warning to Moscow not to meddle in the crisis.

Asked how the crisis could develop, Belonogov said it was impossible to rule out a U.S. military intervention in the event of action against U.S. citizens in Kuwait or an Iraqi attack on Saudi Arabia. But he said he thought that Washington would try to avoid an open conflict with Iraq for the time being, if only because it was not ready to take on a million-man army.