The US is seeking military talks with Russia on Syria, and hopes they could take place "very shortly", Secretary of State John Kerry has said. The US and Russia differ sharply on Syria, and Washington has been concerned about Russia's increased military presence there. "We're looking for ways in which to find a common ground," said Mr Kerry. Moscow has meanwhile said that any request from Syria to send troops would be "discussed and considered". "But it is difficult to talk about this hypothetically," Kremlin spokesman Dmitry Peskov added. Arriving in London for talks with the UAE, Mr Kerry told reporters: "The president believes that military-to-military conversation is an important next step and hopefully will take place very shortly." Russia's foreign ministry offered such talks earlier in this week. A spokeswoman said on Friday: "We have never refused dialogue with the United States. (We) are open to it now on all matters of mutual interest, including Syria," according to Reuters. The two sides have long disagreed over Syria. Russia has been an ally of the Syrian government throughout the four-year civil war, while the US sees President Assad's removal as essential to resolving the crisis. Moscow has increased its presence in the country just as the regime is losing ground to rebel groups. Russia says it is helping Syria fight Islamic State militants. US officials accuse Russia of attempting to establish an air base at Latakia, raising the possibility of air combat missions. In a separate development, a Russian human rights body said it has been contacted by Russian soldiers who fear being sent to fight in Syria. Any secret deployment of troops to Syria would be illegal, said Sergei Krivenko of the Russian Human Rights Council.