Russia has fired cruise missiles at targets in Syria in a major display of military power, with warships in the Caspian Sea more than 1,200km away carrying out the attacks.
Russia says it is targeting the Islamic State of Iraq and the Levant (ISIL) group, but at least some of its air strikes have reportedly hit Western-backed armed groups.
This is the first news of Russia using its navy in its Syria campaign since it began building up its military forces in Syria.
Sergei Shoigu, Russia's defence minister, said on Thursday the navy hit 11 targets in Syria from with missiles fired from ships in the Caspian Sea.
According to state news agency RIA Novosti, Shoigu told Russian President Vladimir Putin all of the targets, which included areas under ISIL control, were destroyed without any civilian casualties reported.
Four ships in Russia's Caspian fleet fired a total of 26 cruise missiles at the targets, the report said, adding that they passed over Iran and Iraq.
The missiles flew nearly 1,500km over Iran and Iraq and struck Raqqa and Aleppo provinces in Syria's north and Idlib province in the northwest, Russian officials said.
ISIL has strongholds in Raqqa and Aleppo, while al-Nusra Front has a strong presence in Idlib.
Western countries, Arab states and Turkey are waging their own bombing campaign against ISIL but want Syrian President Bashar al-Assad - an ally of Russia - to leave power.
They say Russia is using ISIL as a pretext to target Assad's other foes.
Speaking in Rome on Wednesday, Ashton Carter, the Pentagon chief, said the Russian strategy is a "fundamental mistake", and that coalition forces operating in the region will not cooperate with Russia.
The US state department said almost none of Russia's strikes have been aimed at ISIL or fighters tied to al-Qaeda, with most targeting the Syrian opposition.
ANALYSIS: Is Russia flexing its missiles in Syria?
"Greater than 90 percent of the strikes that we've seen them take to date have not been against ISIL or al-Qaeda-affiliated terrorists," John Kirby, the state department spokesman, said.
"They've been largely against opposition groups that want a better future for Syria and don't want to see the Assad regime stay in power."
Putin has stressed the need for cooperation with the US-led coalition fighting ISIL, saying that without cooperation from the US, Turkey and Saudi Arabia the intervention was unlikely to work.
Major ground operation
In Wednesday's other developments, the Syrian army and pro-regime forces launched a major ground operation in Hama province, backed by air support from Russian jets, a military source told AFP news agency.
"The Syrian army and allied forces began a ground operation in the northern parts of Hama province [central Syria]... with fire cover from the Russian air force," the source said.
Russian forces carried out the air strikes on Wednesday morning, in addition to targeting anti-government armed groups with surface-to-surface missiles, said the UK-based Syrian Observatory for Human Rights.
In Aleppo, Russian strikes targeted the towns of al-Bab and Deir Hafer, about 20km east of a military airport currently besieged by ISIL fighters.
The Syrian Observatory also reported that at least six people were killed, including one child, in suspected Russian air strikes in Idlib.
Russian forces have struck 112 targets in war-torn Syria since September 30, Shoigu said.
For his part, Putin said it was too early to talk about the results of Russia's operations in Syria and ordered Shoigu to continue cooperation with the US, Turkey, Saudi Arabia, Iran and Iraq on Syria.
Putin also said that French President France Hollande had voiced the idea of uniting Assad's forces with the so-called Free Syrian Army to fight ISIL.
But a source close to Hollande denied he had said this.
"The president spoke of the necessary presence of the Syrian opposition around the negotiating table." a source close to Hollande said.
"The rest is not a French idea."
Shoigu, the Russian defence minister, said his government had summoned foreign military attaches in Moscow and suggested they supply intelligence on ISIL positions.
"Today we are expecting a reply from our colleagues and we hope they will tell us about those targets which they have," he said.
Shoigu also said Russia was ready to agree a document with the US to coordinate actions in Syria.