Russian President Vladimir Putin, right, shakes hands with his Syrian counterpart, Bashar al-Assad, at the Kremlin in 2006. Russia has been a longtime ally of Assad. (Mikhail Klimentyev/AP)

Russian President Vladimir Putin said Friday that embattled Syrian President Bashar al-Assad is ready to hold parliamentary elections and share power with a “healthy opposition” to end the country’s devastating civil war.

Russia has been a key backer of Assad during the four-year-old conflict, which has killed 250,000 people, displaced millions and empowered the Islamic State and other extremist groups. Putin’s remarks come amid a burst of diplomacy over the war, as well as concern in Washington that Russia is increasing its military support to the Syrian government.

Speaking in the eastern Russian port city of Vladivostok, Putin said that countering “terrorism” in Syria — a term used by Assad’s government to describe the country’s rebels — “should go together with a certain political process” to halt the conflict.

“And the Syrian president, by the way, agrees with that, all the way down to holding early elections, let’s say, to the parliament, establishing contacts with the so-called healthy opposition, bringing them into governing,” the Russian leader said.

There was no immediate comment from Syrian officials on ­Putin’s remarks. And the Russian president did not specify any groups among Syria’s fragmented and weak opposition that would share power with Assad.

Most of Assad’s Syrian opponents demand the leader’s ouster as part of any solution to the war. Russia and Iran, which is also a backer of Assad, reject that.

Meanwhile, officials in Washington have expressed concern over unverified reports of increasing Russian military support to Assad’s forces, including possible troop deployments. This week, images posted to a Twitter account linked to Syria’s al-Qaeda affiliate purported to show advanced aircraft, including a Russian fighter jet and drone, flying over the northwestern province of Idlib.

Russia operates a naval base on Syria’s coast and has provided the Assad government with vital military and logistical support in fighting the rebellion.

“Any military support to the Assad regime for any purpose — whether it is in the form of military personnel, aircraft supplies, weapons or funding — is both destabilizing and counterproductive,” White House press secretary Josh Earnest said Thursday.

The United States is leading a coalition that is carrying out airstrikes against the Islamic State in its strongholds in Syria and Iraq. Russia does not support the coalition’s actions in Syria because U.S. officials do not coordinate attacks with the Assad government.

But even as divisions over Assad persist, Russian officials and their counterparts in the West and in Arab countries have recently engaged in a flurry of diplomacy over how to end the Syrian war.

Analysts say the meetings and discussions have been driven by mutual alarm over the rise of extremist groups in Syria, especially the Islamic State, which may control half of Syria’s territory. Adding to this concern have been significant territorial losses suffered by forces loyal to Assad, whose grip on power shows signs of slipping.

Russia has been at the forefront of the diplomatic frenzy. The meetings have involved Iranian leaders and officials from countries that oppose Assad, such as the United States and Saudi Arabia, which supports Syria’s al­-Qaeda-affiliated Jabhat al-Nusra.

Still, there appears to be mostly pessimism over the prospects of this diplomatic activity because of persistent differences over the Syrian leader’s fate.

Last month, the head of the opposition Syrian National Coalition said after a meeting in Moscow with Foreign Minister Sergei Lavrov that the “Russian leadership isn’t clinging to Bashar Assad.”

In comments earlier this week, however, Lavrov dismissed any such speculation. He described Assad as a leader who is “legitimate because he is an elected president of a U.N. member state.”

Read more:

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Rout shows weaknesses of the Islamic State and U.S. strategy in Syria

A flurry of diplomacy to end Syria’s war raises hope, but even more doubt

Today’s coverage from Post correspondents around the world