WASHINGTON, Feb. 14 (Xinhua) -- U.S. PresidentBarack Obamaon Sunday urgedRussiato play a constructive role inSyriaby halting its air campaign against so-called Syria's moderate opposition forces.

Obama made the call in a phone conversation with his Russian counterpart VladimirPutinon Sunday, theWhite Housesaid in a statement.

The two leaders discussed the decisions and agreements made at the Feb. 11 meeting of the International Syria Support Group (ISSG) and stressed "the importance of rapidly implementing humanitarian access to besieged areas of Syria and initiating a nationwide cessation of hostilities."

"In particular, President Obama emphasized the importance now of Russia playing a constructive role by ceasing its air campaign against moderate opposition forces in Syria," it said.

The two leaders agreed that theUnited Statesand Russia will remain in communication on the important work of the ISSG.

Both the U.S.-led coalition and Russia are conducting military campaigns in Syria.

Russia has been launching air strikes against targets of the terror group Islamic State inside Syria since last September, but the U.S. has accused Moscow of bombing moderate opposition forces in Syria in order to help sustain the rule of Syrian President Bashar al-Assad.

The ISSG meeting, sponsored by the the U.S. and Russia, agreed on a nationwide cessation of hostilities to be implemented soon in Syria, and on humanitarian aid delivery to besieged areas in the country.

Obama also urged "combined Russian-separatist forces to fulfill their Minsk obligations, especially adhering to the cease-fire and ensuring that the Special Monitoring Mission of the Organization for Security and Cooperation in Europe (OSCE) has full access to all areas of eastern Ukraine, including the international border."

"The President reiterated the importance of quickly reaching agreement on the modalities for elections in eastern Ukraine that comply with OSCE standards," the White House statement said.

On Ukraine, Putin expressed the hope that Kiev would take practical steps to meet its obligations under the Minsk deal as soon as possible, including constitutional reform, establishing direct dialogue with the two self-proclaimed republics in eastern Ukraine, and amendments to the law on special status of the Donbass region, according to an earlier Kremlin statement.

Relations between Russia and the Western countries have been undermined by disputes over the Syria and Ukraine issues, with both sides waging a sanction war and cutting dialogues.

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