WASHINGTON, June 25 -- U.S. President Barack Obama and his Russian counterpart Vladimir Putin on Thursday discussed the situations in the Middle East and Ukraine in a phone conversation, the White House said.

The two leaders discussed the "increasingly dangerous" situation in Syria and underscored the importance of continued unity among world powers in the ongoing talks on Iran's nuclear program, the White House said in a statement.

The White House said that the call was initiated by Putin.

With the June 30 deadline looming, the P5+1 group, namely Britain, China, France, Russia, the United States and Germany, is making final efforts to reach a comprehensive deal with Iran on its controversial nuclear program.

On the Ukraine issue, Obama reiterated the need for Russia to fulfill its commitments under the Minsk agreement reached in February, including the removal of all Russian troops and equipment from Ukraine territory.