UN chief Ban Ki-moon is expected to press China's leaders Wednesday to back tougher action to stop violence in Syria before a Security Council showdown over a resolution threatening sanctions.

Ban will meet Chinese President Hu Jintao in Beijing before the vote on the Western resolution that links the renewal of a UN mission in Syria with a threat to impose sanctions if the regime does not pull back heavy weapons.

But it will be a difficult task for the UN secretary general to persuade Beijing, which has repeatedly warned against outside intervention in Syria, to back the action being pushed for by Western powers.

China, one of five veto-wielding members of the Security Council, has twice joined with President Bashar al-Assad's main ally Russia in blocking resolutions at the council.

Ban has already urged China to use its influence to back a peace plan by UN-Arab League envoy Kofi Annan, who is calling on the Security Council to order "consequences" for any failure to carry out his six-point plan.

Assad has agreed to the plan, which includes the withdrawal of heavy weapons, but failed to carry it out.

As Ban headed for China, Beijing's determination to stick to its guns was underlined when a top, state-run newspaper again warned against international intervention.

"The life of Syria's current political leadership can only be determined by the Syrian people. This is an internal matter and the international community should respect that," the People's Daily said in an editorial.

Russia has branded as "blackmail" the bid to link renewal of the UN mission to the threat of sanctions, and had said it would block the new resolution, instead proposing its own draft.

But Moscow struck a more conciliatory tone on Tuesday after Annan met Russian President Vladimir Putin.

Putin vowed to do everything to support Annan's plan for ending the violence, while Foreign Minister Sergei Lavrov said he could "see no reason why we cannot also agree at the UN Security Council. We are ready for this".

The current 90-day UN mission in Syria ends on Friday and if no resolution is passed by then, it would have to shut down this weekend, according to diplomats.

Following talks with Hu, Ban will also meet Vice President Xi Jinping -- set to become China's president next year -- as well as top foreign policy advisor Dai Bingguo and Foreign Minister Yang Jiechi, diplomats said.

Ban, who is officially in Beijing for a China-Africa summit, has said that international inaction on Syria would be giving "a license for further massacres."

In Syria on Tuesday, troops blasted Damascus neighbourhoods with helicopter gunships and tank fire, witnesses said, after rebels announced an escalation of their battle for control of the capital.

Fighting between Assad's forces and rebels of the Free Syrian Army has raged in Damascus since Sunday, with some activists saying it marked a "turning point" in the 16-month revolt against the regime.