The United Nations is planning a peacekeeping force for Syria if a proposed ceasefire takes hold in the conflict-torn Middle East country, which has been suffering from a political crisis since March 2011, said Herve Ladsous, the UN under-secretary-general for peacekeeping operations, here on Monday.

"I would confirm that, of course, we are giving a lot of thought to what would happen if and when a political solution or at least a ceasefire would emerge," Ladsous told a press conference.

The UN peacekeeping chief made the statement as the UN-Arab League joint special representative for Syria, Lakhdar Brahimi, is in the Syrian capital Damascus to mediate a ceasefire between government troops and armed opposition fighters during the Islamic festival of Eid al-Adha, which starts on Friday.

The peacekeeping force is one of the various contingency plans for bringing an early end to the 19-month Syrian crisis, Ladsous noted.

However, it is too early to say at this stage how many would be needed if the United Nations decides to send peacekeepers to Syria, he added.

"There are a number of hypotheses, but I think at this stage one can only say that it certainly would be premature to mention a figure because it would depend on the situation (and) on the tasks, " he said.

The deployment of a UN peacekeeping force in Syria needs a unanimous decision by the 15 members of the UN Security Council, which, under the UN Charter, has the primary responsibility for the maintenance of international peace and security.

A UN observer mission was sent to Syria for three months earlier this year, but the 300 unarmed personnel were eventually pulled out of the Middle East country due to mounting dangers. A small, civilian liaison office was set up later in Damascus.