The Arab League rejected a request by Damascus to amend plans for a 500-strong monitoring mission to Syria, and President Bashar al-Assad said he would not bow to international pressure to stop a crackdown against protesters.

Within hours of Assad ignoring a deadline to halt the bloody crackdown, residents said two rocket-propelled grenades hit a major ruling party building in Damascus on Sunday, the first such reported attack by insurgents inside the capital.

Confronted since March by street demonstrations against 41 years of rule by his family, Assad said he had no choice but to pursue his crackdown on unrest because his foes were armed.

The conflict will continue and the pressure to subjugate Syria will continue. Syria will not bow down, he told Britain's Sunday Times newspaper.

The Arab League, alarmed at the mounting death toll in Syria, rejected Damascus's request to alter a plan for the fact-finding mission, which would include military personnel and human rights experts.

The additions requested by the Syrian counterpart affect the heart of the protocol and fundamentally change the nature of the mission, Arab League Secretary General Nabil Elaraby said in a letter to the Syrian government.

Syria's Foreign Minister Walid al-Moualem said the plan as it stood compromised the country's sovereignty but Damascus had not rejected the mission

Moualem said the proposed mission had pervasive jurisdiction that reaches the level of ... violating Syrian sovereignty and that he would send the Arab League a letter with questions about its role.

We will reply to the Arab League secretary general by responsibly presenting a number of queries, he told a televised news conference in the Syrian capital.

ARAB LEAGUE DEADLINE

The Cairo-based League had given Damascus three days from a meeting on November 16 to abide by a deal to withdraw military forces from restive cities, start talks between the government and opposition and pave the way for an observer team.

It was not immediately clear what action the Arab League would take after the deadline passed unheeded by Damascus. The pan-Arab body had threatened sanctions for non-compliance, and it has already suspended Syria's membership.

Although the time-frame has ended, there have been no meetings or calls for meetings except at the level of delegations (to the League), a representative of one Arab state at the League told Reuters.

In a statement, the League said it remained committed to a peaceful, Arab-engineered solution to the Syrian upheaval, touched off by other Arab popular revolts that have overthrown the autocratic leaders of Egypt, Tunisia and Libya this year.

Syrian authorities blame the violence on foreign-backed armed groups which they say have killed some 1,100 troops and police. By a United Nations account, more than 3,500 people, mostly civilians, have been killed in the unrest.

Assad signalled no retreat from his iron-fist policy in a video released after his forces killed 17 more protesters on Saturday.

The only way is to search for the armed people, chase the armed gangs, prevent the entry of arms and weapons from neighbouring countries, prevent sabotage and enforce law and order, he said in footage published on the Sunday Times website.

Assad said there would be elections in February or March when Syrians would vote for a parliament to create a new constitution and that would include provision for a presidential ballot.

An opposition group, the Syrian National Council, said it envisaged a transitional period lasting up to one-and-a-half years if Assad was toppled.

But some prominent Assad opponents said more work was needed on uniting the opposition to bring about his downfall.

LATEST VIOLENCE

On Sunday, the Syrian Observatory for Human Rights said troops manning roadblocks in Homs fired on residential areas and wounded three protesters.

In the nearby town of Talbiseh, government forces delivered the bodies of two men arrested last month and in Idlib another two civilians were killed in military operations, the British-based group said.

The Syrian Free Army, comprising army defectors and based in neighbouring Turkey, claimed responsibility for the attack on the Baath Party building in Damascus.

There was no independent verification of the claim and Moualem denied that any attack had taken place. But a witness said security police blocked off the square where the building was located and reported seeing smoke rising from it and fire trucks in the area.

The attack was just before dawn and the building was mostly empty. It seems to have been intended as a message to the regime, said the witness, declining to be identified.

Syrian authorities have barred most independent journalists from entering the country during the revolt, making it difficult to verify accounts from activists and officials.

It was the second reported hit on a high-profile target in a week, underscoring a growing challenge to Assad - who blames armed terrorist acts for the unrest - from a nascent insurgency alongside mostly peaceful protests that have persisted despite the intensifying crackdown.

Assad, who inherited power from his father in 2000, is a member of the Alawite minority community, an offshoot of Shi'ite Islam that dominates the state, the army and security apparatus in the majority Sunni Muslim country of 20 million.

The Syrian Free Army said the attack was a response to the refusal of Damascus to release tens of thousands of political prisoners and return troops to barracks, as called for by the plan agreed between the Arab League and Damascus.

Non-Arab Turkey, once an ally of Assad, is also taking an increasingly tough attitude to Damascus.

Turkish newspapers said on Saturday Ankara had contingency plans to create no-fly or buffer zones to protect civilians in neighbouring Syria if the bloodshed worsens.

(Additional reporting by Erika Solomon in Beirut and Dina Zayed, Ayman Samir and Omar Fahmy in Cairo; Editing by Dominic Evans and Ralph Gowling)