As a top Russian official met with Syrian President Bashar al-Assad in Damascus on Wednesday, Foreign Minister Sergei Lavrov declared that Moscow will not try to persuade Assad to step aside.

Russia “has no experience in this kind of ‘political engineering,’” Lavrov told participants in a high-level forum in the resort town of Valdai, northwest of Moscow, according to a social media post by Gleb Pavlovsky, a former top Kremlin aide who was in attendance.

Russia has been Assad’s staunchest defender in the 21 / 2-half-year-long conflict in Syria, but it reached an agreement with the United States on Saturday under which Assad will be required to relinquish Syria’s chemical weapons stockpile.

The agreement removed the threat of an immediate U.S. military strike on Syria, and Russia has made clear that it still supports the Assad regime in its struggle against rebel forces.

The Foreign Ministry did not disclose any details about the meeting Wednesday afternoon between Assad and the deputy foreign minister, Sergei Ryabkov.

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Late Tuesday night, the Syrian foreign minister gave Ryabkov what was described as evidence that an Aug. 21 chemical weapons attack in Ghouta, outside Damascus, was the work of rebel forces hoping to provoke a Western military intervention, Russian news services reported.

Lavrov said Russia would hand that evidence over to the U.N. Security Council.

The United States, France and other countries contend that the Aug. 21 attack was carried out by Assad’s government and insist that a U.N. inspectors’ report released Monday points to the government’s guilt, even if it doesn’t explicitly assign blame.

In Damascus, Ryabkov called the U.N. report “political” and incomplete.

The U.N. inspectors said they had examined a chemical weapon with Cyrillic writing on it. Although it has long been believed that the Soviet Union helped sponsor Syria’s chemical weapons program, a top Kremlin official dismissed that contention at the Valdai forum.

The Soviet Union never exported warheads with sarin — a nerve gas — to foreign countries, Sergei Ivanov, head of the presidential administration, said, according to the Interfax news agency.

“Now imagine: an old, ancient Soviet rocket and warhead, which came out of nowhere. This alone should raise big questions,” Ivanov said. “And second, the committee found large tanks at the site . . . near which traces of sarin were found. Not a single army of the world ever uses such tanks. So they were almost surely made in someone’s backyard.”

Former U.S. attorney general Ramsey Clark, known for his defense of controversial international figures including former Iraqi dictator Saddam Hussein and Liberian warlord Charles Taylor, was also among Assad’s visitors on Wednesday. During the meeting with Clark, Assad stressed that the United States’ policy based on “waging wars” does not serve the interests of its people, the official Syrian Arab News Agency (SANA) reported.

Loveday Morris in Beirut contributed to this report.