UN Secretary General Ban Ki-moon is due to arrive in Turkey on a regional tour focusing largely on the conflict in Syria, BBC News reported.

Mr Ban will visit refugee camps in the south where some 200,000 Syrians have taken refuge from the fighting across the border.

He will also hold talks in Ankara with Prime Minister Recep Tayyip Erdogan.

The visit comes as governments continue to warn Damascus not to use chemical weapons against rebel forces.

Mr Ban says that he has written to President Bashar al-Assad to warn that the use of such weapons would have "serious consequences".

Speaking in the Iraqi capital Baghdad on Thursday, Dec 6, he said President Assad should be "brought to justice" if his regime used chemical weapons.

"I have expressed my gravest concerns to (the) government of Syria and I have sent a letter directed to President Assad a couple of days ago," Ban said. "I have warned that in any case, if chemical weapons is used, then whoever (it) may be will have to be brought to justice, and it will create serious consequences to those people."

NATO recently approved the deployment of Patriot anti-missile batteries along Turkey's border with Syria. The long-expected move came amid growing fears that Syria could use chemical weapons.