Russian President Vladimir Putin visited Syria on Tuesday and met officials including President Assad, state media reported.

Putin's surprise visit, which takes place on the day of Orthodox Christmas, and just beofre a planned trip to Turkey, is the second to the war-torn country where Russian troops have been fighting alongside government forces since 2015.

The visit comes amid heightened tensions between Iran, a key Syrian ally, and the United States, following the killing of a top Iranian general in a U.S. airstrike in neighboring Iraq.

U.S. troops are based in eastern Syria, making the country a potential site of conflict with Iran.

Kremlin spokesman Dmitry Peskov said Putin visited the Russian command post in Damascus and met President Bashar Assad there. The two leaders were presented with military reports on the situation in different regions of Syria.

In his conversation with Assad, Putin said that “a huge distance has been covered in terms of restoring Syria’s statehood and territorial integrity,” Peskov said.

Syrian state news agency SANA showed a photograph of Putin smiling as he shook Assad's hand and said they had listened to a military presentation by the head of Russian forces in Syria.

Putin and Assad discussed recent developments in the region and plans to "eliminate terrorism" in the Idlib region, one of the last pieces of Syrian territory held by anti-Assad insurgents, SANA reported.

Putin also delivered greetings to Russian forces in Syria.

Open gallery view Syrians hold posters of Assad and Putin during a pro-Syrian government protest in front of the Russian Embassy in Damascus, Syria, March 4, 2012 Credit: אי.פי

Accompanied by Assad, Putin visited the Old City of Damascus including, the 8th century Umayyad mosque and an ancient church.

"I think Putin is there to reinforce the Russian position in Syria and with the person of Syrian President Bashar al-Assad, especially as Iran's position has been indelibly weakened, since Soleimani was essentially Iran in Syria," said David Lesch, an expert on Syria.

The last time Putin visited Syria was in 2017 when he declared that mission for Russian troops has been accomplished. Russia has been a main backer of Assad and has tipped the balance of power in his favor over the past four years with government forces now in control in most of the country.

Putin is due to hold talks on Wednesday with President Tayyip Erdogan in Turkey, which has sent forces into much of northern Syria to beat back Kurdish-led forces that had been backed by the United States.

Syria's conflict began in March 2011, and has left more than 400,000 people dead.

Last week U.S. warplanes attacked bases of Iran-backed Iraqi fighters in western Iraq and eastern Syria killing 25 and wounding dozens others.

Soleimani's death has sparked calls across Iran for revenge against America for a slaying that’s drastically raised tensions across the Middle East.

The U.S. government warned ships of an unspecified threat from Iran across all the Mideast's waterways, crucial routes for global energy supplies.

Meanwhile, the U.S. Air Force launched a drill with 52 fighter jets in Utah, just days after President Donald Trump threatened to hit 52 sites in Iran.

Merkel invited

German Chancellor Angela Merkel will travel to Russia on January 11 for talks with Putin on the crisis triggered by the killing of Qassem Soleimani, the Kremlin press service said.

Merkel will make the trip on the invitation of Putin and they will also discuss the situation in Syria, Libya and Ukraine, it said.

Merkel's spokesman said German Foreign Minister Heiko Maas would accompany her on the trip.