Syrian President Bashar al Assad says his government has a duty to "eliminate terrorists" to protect its people, ruling any solution to the crisis imposed from outside the country.

Assad's rare one-hour interview coincided with a marked escalation of violence inside Syria and a flurry of diplomatic activity ahead of a planned meeting in Geneva in an effort to end spiralling violence.

Diplomats said the talks involving UN Security Council members and key regional countries would focus on a proposed transition plan to open the way for a unity government.

"The responsibility of the Syrian government is to protect all of our residents. You have a responsibility to eliminate terrorists in any corner of the country," Assad told Iranian state television.

"When you eliminate a terrorist, it's possible that you are saving the lives of tens, hundreds, or even thousands."

The besieged Syrian leader rejected any solution imposed from outside the country.

"We will not accept any non-Syrian, non-national model, whether it comes from big countries or friendly countries. No one knows how to solve Syria's problems as well as we do."

Assad said he did not believe the crisis would result in military action in Syria, saying that what took place in Libya was "not a solution to be copied because it took Libya from one situation into a much worse one. We all now see how the Libyan people are paying the price"

Assad also criticised Syria's neighbour Turkey, relations with which have worsened following the shooting down of one of its military planes by Syrian forces last Friday.

"What we see now shows the stance of some Turkish officials but not all," he said. "The policies of the Turkish officials lead to the killing and bloodshed of the Syrian people."

While the United States and its allies have called for Assad to step aside, Iran and Russia have continued to support the Syrian leader and criticised what they say is foreign interference the country.

In recent years Iran's Shiite theocracy has strengthened its alignment with Syria's nationalist secular government to further its opposition to Israel and as a counterweight against Sunni powers in the region such as Saudi Arabia.

Western diplomats say that in recent months Tehran has boosted its support for Assad through training, weapons and communications expertise to assist Syrian forces in fighting rebel groups.

Assad was scornful of such reports that Iranian forces and fighters from Lebanon's militant Hezbollah resistance movement were helping to direct Syrian army operations.

"This is a joke that we hear many times in order to show that a rift has been created within the army and that therefore there is not an army."

The Syrian leader thanked Iran for being such a loyal friend and said Damascus would repay such loyalty.

"We are on the same front and the name of this front is being independent and making national decisions." 

CAPITAL ROCKED

Rebel forces attacked Syria's main court in central Damascus overnight , as Turkey deployed troops and anti-aircraft rocket launchers to the Syrian border.

There was a loud explosion and a column of black smoke rose over Damascus, an Assad stronghold that until the last few days had seemed largely beyond the reach of rebels. State television described it as a "terrorist" blast.

Dozens of wrecked and burning cars were strewn over a car park used by lawyers and judges. State news agency SANA said three people were wounded by the bomb hidden in one of the cars.

The guerrilla attack in Damascus coincided with a Turkish military build-up on its border to the north and a growing sense of urgency in Western- and Arab-backed diplomatic efforts to forge a unity government and end 16 months of bloodshed.

Turkish military convoys moved slowly towards the Syrian frontier, reacting to Syria's shooting down of the Turkish warplane over the Mediterranean. A Turkish official said they were reinforcing air defences.

A first substantial convoy of about 30 military vehicles, including trucks loaded with anti-aircraft missile batteries dispatched from Turkey's coastal town of Iskenderun, was moving slowly towards the Syrian border 50 km away.

A Reuters reporter near the town of Antakya saw the convoy moving out of the hills and through small towns on a narrow highway escorted by police.

Early on Thursday, another convoy left a base at Gaziantep and headed for Kilis province, the site of a large camp for Syrian refugees. Video from the DHA agency showed the convoy, of about 12 trucks and transporters, filing through the gates of the base past the hanging Turkish red flag with white crescent moon and star.

David Hartwell, Middle East analyst at IHS Jane's called the Turkish action a 'pragmatic, rational response' after the shooting down of the Turkish aircraft, that Syria insists was flying low and fast in Syrian air space. "Damascus has been warned once. I doubt there will be a second warning."

Turkey, in the front line of Western efforts to press Assad from power, hosts over 33,000 Syrian refugees on its south-eastern border as well as units of the rebel Free Syria Army (FSA).

- AP