China refused again on Thursday to say whether it would attend a global conference aimed at ending the violence in Syria, as a bloody crackdown on protesters intensified.

Moscow has already said it will boycott the "Friends of Syria" meeting, which will bring together senior Arab and Western diplomats as well as representatives of the Syrian opposition in Tunis on Friday.

Pressed on whether China would send a representative, foreign ministry spokesman Hong Lei would only say that Beijing was "still studying the role and mechanism of the meeting".

Beijing, which has a long-held policy of non-interference in other countries' affairs, has been strongly criticised for joining Russia in vetoing UN Security Council resolutions on the violence in Syria.

China has repeatedly defended its decision to veto the latest resolution, and said it was "willing to play a constructive role with all sides for the peaceful resolution of the Syrian crisis".

An influential Chinese newspaper this week warned that Western support for Syrian rebels could trigger civil war in the violence-hit nation.

But as the bloodshed in Syria continues, Beijing is under increasing pressure to alter its neutral stance.

The United States has encouraged China to attend the meeting, saying to do so would be "a positive sign of its willingness to work with the rest of us to try to end the violence".

More than 6,000 people have died in nearly a year of upheaval in Syria, as President Bashar al-Assad's hardline regime seeks to snuff out a revolt that began with peaceful protests in March 2011.