In a telephone conversation on Thursday, the two ministers strongly condemned any use of chemical weapons by terrorists in Syria and expressed deep concern over the escalation of tensions in the Arab country.

On Wednesday, the head of the so-called opposition Syrian National Coalition, George Sabra, claimed that 1,300 people were killed in a government chemical attack on militant strongholds in Damascus suburbs of Ain Tarma, Zamalka and Jobar.

The Syrian government, however, has vehemently rejected allegations that it used chemical weapons, saying the accusations were fabricated to distract a visiting team of the UN chemical weapons experts and to cover up militants' losses.

Syria has been gripped by deadly unrest since 2011. The United Nations says more than 100,000 people have been killed and a total of 7.8 million others displaced since the outbreak of the violence.

Lavrov also congratulated Zarif on his endorsement and appointment as foreign minister, calling for the continuation of the close cooperation between Tehran and Moscow to help secure their interests, consolidate regional ties and support global security and stability.

Highlighting the need for continued consultations between the two sides, the two ministers also discussed major regional and international developments as well as issues of mutual interest, including Iran’s nuclear energy program.

SHI/SHI