MOSCOW, April 18./TASS/. In a telephone conversation on Monday, the presidents of Russia and the US, Vladimir Putin and Barack Obama, discussed the situation in Syria, confirming a bid to contribute to the strengthening of the cessation of hostilities regime in that country initiated by Russia and the US, and to ensure access of humanitarian aid to Syrian regions, the Kremlin press service reports, noting that the conversation was initiated by the US.

"Putin put an accent on the need for moderate opposition distancing itself as soon as possible from IS and Jabhat al-Nusra, as well as for shutting the border between Syria and Turkey from where gunmen keep infiltrating and arms are supplied to extremists," the press service said.

They also agreed to "keep boosting coordinated effort of the two countries in the Syrian direction, including through secret services and defense agencies," it went on. "With this aim additional measures will be worked out for prompt reaction to the existing violation of the ceasefire regime," it said.