Russia has agreed the United States should be involved in talks on Syria's future planned for this month, Turkey's top diplomat said, as a series of explosions rocked Damascus, AFP reports.

Moscow and Ankara last month brokered a fragile ceasefire for the war-torn country, but without the involvement of Washington, a negotiator in previous agreements.

"The United States should be definitely invited, and that is what we agreed with Russia," Foreign Minister Mevlut Cavusoglu told journalists in Geneva on Thursday, January 12 after an international conference on Cyprus.

The talks in Astana are expected to take place on January 23.

The truce -- which does not include Fateh al-Sham, formerly known as Al-Nusra Front, or the Islamic State group -- has brought quiet to large parts of the country, but violence has continued in some areas.

On Thursday a suicide bomber killed at least eight people in a rare attack on a high-security district of Damascus, a monitor said, while a series of explosions later ripped through a military airport on the western outskirts of the city.

"Eight people died when a suicide bomber targeted Kafr Sousa" in the southwest of the capital, the Syrian Observatory for Human Rights said.

"At least four of them were soldiers, including a colonel," Observatory director Rami Abdel Rahman said.