US President Barack Obama was on Monday set to announce plans to send up to 250 more special forces to Syria.

US President Barack Obama was on Monday set to announce plans to send up to 250 more special forces to Syria.

Obama was in Germany for talks with Chancellor Angela Merkel, and both were to be joined later by the leaders of Britain, France and Italy in a meeting expected to focus on the fight against the Islamic State group.

On Sunday Obama had pressed for all parties to the Syrian conflict, including the regime's ally Russia, to return to the negotiating table and "reinstate" an internationally-brokered ceasefire.

"I spoke to President Vladimir Putin early last week to try to make sure that we could reinstate the cessation of hostilities," Obama told a news conference in the northern city of Hanover.

Deputy National Security Advisor Ben Rhodes said Obama would on Monday announce his decision to deploy to Syria another 250 special forces.

"This brings the number of US special forces to roughly 300," he said.

US troops in Syria are mandated to advise and assist Syrian opposition and anti-ISIL (so-called Islamic State in Iraq and Levant Takfiri group) militants.

"What we have seen is the small team that we have put in to Syria several months ago has been very effective in serving as a force multiplier. They are able to provide advice and support to the forces that are fighting against ISIL on the ground," Rhodes said.