Russian President Vladimir Putin phoned U.S. President Barack Obama on Thursday, their first call since February, to discuss Iran nuclear talks, "the increasingly dangerous situation in Syria" and the need to counter Islamic State militants, the White House said in a statement.

"The leaders discussed the increasingly dangerous situation in Syria, and underscored the importance of continued P5+1 unity in ongoing negotiations to prevent Iran from acquiring a nuclear weapon," the White House said.

Obama also told Putin that Russia needs to live to up to the terms of a ceasefire deal withUkraine, "including the removal of all Russian troops and equipment from Ukrainian territory," the White House said.