MASNAA, Lebanon — Russia, a key Syrian ally, began evacuating its citizens from Syria on Tuesday as the civil war gathered momentum in the capital Damascus with intense fighting around the international airport.
The evacuation was the strongest sign yet of Moscow’s waning confidence in the ability of its ally President Bashar Assad to hold onto power. The UN chief said Tuesday that a diplomatic conclusion to the war seems unlikely.
US State Department spokeswoman Victoria Nuland said the Russian evacuations indicate ‘‘the continued deterioration of the security situation and the violence that Assad is leading against his own people.’’
Four buses carrying about 80 people, mostly women and children, crossed out of the country into neighboring Lebanon in the early afternoon. They were bound for Beirut to fly home in two planes that Russia sent. They apparently were not flown home out of Damascus because of the fighting around the airport there.
Russia announced the beginning of the evacuations on Monday, saying it would take out 100 nationals. The Russian Foreign Ministry says there are tens of thousands of Russians living in Syria.
The officials said thousands more evacuations could follow.
Russia has been Assad’s main ally since the Syrian uprising began in March 2011, selling arms, providing technical support, and, along with China, using its veto power in the UN Security Council to shield Damascus from international sanctions over the Syrian regime’s crackdown on dissent.
But in recent months, Russia has started distancing itself from Assad. President Vladimir Putin said last month that he understands Syria needs change and that he was not protecting the Syrian ruler.
Officials at the Russian Embassy in Damascus said they have several thousand citizens registered as living in Syria. The officials, speaking on condition of anonymity because they were not authorized to talk to reporters, said some of the people who were being evacuated Tuesday have lost their houses and need Russian government assistance to leave.
The officials downplayed the evacuation effort, denying that they are assisting their nationals’ departures from Syria because of the deteriorating security situation.
One of the officials, who identified herself only as the embassy’s head of protocol, said the government was simply responding to those who had asked for help in leaving Syria, suggesting they were mostly Russians living in areas where the fighting is fiercest.
In Moscow, Deputy Foreign Minister Andrei Denisov dismissed reports that the evacuations were the beginning of a Russian exodus. He said that Russian planes landed in Beirut to deliver humanitarian aid at the Syrian government’s request, and would take home those who wanted to leave.
‘‘There is no plan to take everyone out,’’ Denisov said. ‘‘Since the planes have arrived there, and some people with children want to leave.’’