The Syrian military said Monday it has temporarily halted combat operations in the south ahead of Russian-sponsored cease-fire talks with the rebels.

The announcement came after a large Syrian rebel faction in the south said it would not attend the talks in the Kazakh capital, Astana, because the government was not abiding by previous cease-fire agreements.

The two sides have held four previous rounds of talks in Kazakhstan since January in parallel to U.N.-brokered peace talks in Geneva. Neither process has made much progress. A cease-fire declared in May, which is built around so-called “de-escalation zones,” has been repeatedly violated.

The military announcement, carried on Syrian state media, did not link the present pause to the Astana talks, but said it would run until July 6. Delegates are expected to begin meeting with a U.N. mediator and other diplomats on July 4.

Syrian Deputy Foreign Minister Faisal Mekdad meanwhile questioned the credibility of the Organization for the Prohibition of Chemical Weapons, saying the inspectors had failed to visit key sites linked to a nerve gas attack that killed 89 people.

Mekdad dismissed an OPCW report released last week confirming the use of sarin gas on the opposition-held town of Khan Sheikhoun in April. He said the inspectors refused government invitations to visit the site of the attack in northern Syria or the military airport allegedly linked to it.

The report, which drew on samples taken to Turkey, did not say who was responsible for the attack. The results will be turned over to a joint commission with the U.N. to apportion blame.

Syria insists it has never used chemical weapons.

The Pentagon said last week that intelligence showed the Syrian military preparing another chemical weapons attack at the same air base the U.S. said was used to launch the Khan Sheikhoun attack on April 4. U.S. President Donald Trump ordered punitive missile strikes on the Shayrat air base less than a week after that attack.

Russia, a close ally of Syrian President Bashar Assad’s government, called the U.S. statement a provocation.

In a press conference Monday, Mekdad said the idea the Syrian government would use chemical weapons was “impossible,” given that it was already winning the war against its opponents.

“Why would the Syrian government undertake such stupid measures?” he asked.

(AP)