Wednesday, September 30, 2015 8:37 AM EDT report nytime President Vladimir V. Putin of Russia escalated the stakes in his contest with the West over influence in the Middle East on Wednesday, as Russian pilots carried out their first airstrikes in Syria. Russian warplanes dropped bombs near the central city of Homs, according to American officials in Washington, who spoke on the condition of anonymity because they were not authorized to make a public statement. Moscow informed American officials in advance, they said. The attack came hours after Mr. Putin pushed a measure through the upper house of Parliament approving the use of Russian military forces abroad. Russian officials and analysts portrayed the move as an attempt both to fight Islamic State militants and to try to ensure the survival of President Bashar al-Assad of Syria, Russia’s main ally in the Middle East. But Russian intervention would most likely prolong and complicate the war, as it would keep Mr. Assad in office and would add Russian forces to the already complicated patchwork of forces deployed there. Sergei B. Ivanov, Mr. Putin’s chief of staff, appealed to the upper house, the Federation Council, for the measure, describing it as an open-ended deployment of the Russian Air Force to support Mr. Assad — at his request — in his fight against the Islamic State.