UN and Arab League special envoy Kofi is due to meet Syrian President Bashar al-Assad to discuss the future of the six-point peace plan.

"We know that [Annan] is coming up against countless obstacles but his plan should not be allowed to fail, it is a very good plan," Assad told German television channel Das Erste.

"The biggest obstacle is that many countries do not even want this plan to succeed, so they offer political support and continue to provide the terrorists in Syria with arms and money," Assad said.

The peace plan has been ineffective so far - even after UN monitoring teams arrived in Syria.

The UN observers recently suspended their operations due to increasing violence.

Assad accused external forces of hindering the peace process in Syria. He blamed the US for providing political support to the rebels and accused other countries, such as Saudi Arabia, Qatar and Turkey, of supplying arms to the "gangs" seeking to overthrow his regime.

US Secretary of State Hillary Clinton said the opposition forces in Syria were becoming more effective and a "catastrophic assault" by the rebel forces on the Assad administration could not be ruled out if the violence continues to escalate.

"The sooner there can be an end to the violence and a beginning of a political transition process, not only will fewer people die, but there is a chance to save the Syrian state from a catastrophic assault that would be very dangerous not only to Syria but to the region," Clinton said in Tokyo, where she was attending the Conference on Afghan Aid.

"The sand is running out of the hour glass," she said.

The Syrian Observatory for Human Rights reported 30 people were killed in bombing Meanwhile, violence continued in Syria and at least 30 people were killed in the bombing by Assad forces on Sunday, according to a Reuters report quoting the Syrian Observatory for Human Rights.

Syria tested firing live missiles from ships and helicopters to demonstrate its military capability in the event of an external aggression, according the state news agency Sana.

"Our navy forces started to conduct an operational tactical manoeuvre with live ammunition, during which naval and coastal rockets were fired," Sana said in its report.