Annan claims Syria has reached "tipping point" after yearlong conflict

London - UN-Arab League envoy to Syria Kofi Annan has said the country has reached a "tipping point", after more than a year of conflict.

Annan made the remarks after talks with Syrian President Bashar al-Assad and told reporters the six-point international peace plan for Syria was not being implemented "as it must be".

President Assad said the success of Annan's peace plan depended on halting 'terrorist actions' and stopping arms-smuggling.

"I appealed to him [Mr Assad] for bold steps now - not tomorrow, now - to create momentum for the implementation of the plan," the BBC quoted Annan, as saying.

Calling on the Syrian government and all government-backed militias to show "maximum restraint", he also asked the "armed opposition to cease acts of violence".

Meanwhile, several Western states announced they were expelling Syrian diplomats following Friday's massacre in the Houla region, leaving 108 dead.

The United States, France, the UK, Germany, Italy, Spain, Canada, Australia, the Netherlands and Switzerland all took action on Monday to expel Syrian diplomats over Friday's killings.

However, Syrian leaders insisted that the massacre was the 'work of terrorists', aimed to derailing the peace process and provoke intervention by Western powers.