* Norwegian U.N. peacekeeper due to fly in
* Full peacekeeper mission would need new U.N. resolution
* Homs quarter bombarded for 17 days
BEIRUT, April 5 (Reuters) - A senior Norwegian U.N. peacekeeper flies into Damascus on Thursday to try to broker an agreement that will allow observers to be deployed across Syria to monitor a ceasefire demanded by an international peace plan.
Syrian President Bashar al-Assad has accepted the plan, which calls for him to withdraw heavy weapons from cities, and his ally Russia said Syrian forces had begun to pull back.
But opposition activists on Wednesday reported no let-up in Assad's crackdown on what began over a year ago as a peaceful uprising and has since turned at least partly into an armed insurgency.
They said at least 80 people, 18 of them soldiers, had been killed in the previous 24 hours. Shells rained down on Homs, the city of 1 million that has suffered most in the uprising.
"Since this morning they have been shelling Khalidiya neighbourhood, that is in its 17th day," said activist Hadi Abdullah by telephone from Homs.
Human rights group Amnesty International said it had counted 232 deaths since Syria accepted Annan's plan on March 27.
U.N.-Arab League special envoy Kofi Annan has ordered Norwegian Major-General Robert Mood, who served as head of mission of UNTSO, the U.N. peacekeeping operation in the Middle East, to take an advance team to Damascus anyway.
Mood's job is to prepare the ground for an observer mission comprising up to 250 unarmed staff, his spokesman Ahmad Fawzi said. Such a mission would require a U.N. Security Council resolution before deploying.
Annan has brokered a six-part peace plan that provides for an April 10 withdrawal of Syrian forces, to be followed by a ceasefire by rebel forces within 48 hours.
Assad's government issued its latest official death toll for the 12-month uprising. It told the United Nations that 6,044 people had been killed, of whom 2,566 were soldiers and police.
The United Nations itself says Assad's forces have killed more than 9,000 people in the past year.
Assad's acceptance of a troop withdrawal has met with scepticism among the Syrian opposition and its Western and Arab supporters.
"The Syrian authorities have said they will do that by April 10," British Foreign Secretary William Hague said in London.
"There is no sign of them doing it so far. Attacks on the citizens, the civilians of their country have continued, the murder, oppression, and torture of the regime has continued ..."
But Russian Deputy Foreign Minister Gennady Gatilov said the withdrawal was already under way.
"Kofi Annan is continuing his efforts, the Syrian side has begun withdrawing forces from cities. The main thing now is for all sides to carry out Annan's proposals," Interfax news agency quoted Gatilov as saying in Moscow.
Gatilov's boss, Foreign Minister Sergei Lavrov, attacked the "Friends of Syria" group of Western and Arab nations which met at the weekend, saying it was undermining Annan's mission.
"Everyone has supported Kofi Annan's plan, but decisions at the 'Friends of Syria' group meeting aimed at arming the opposition and at new sanctions undermine peace efforts," state-run Itar-Tass quoted Lavrov as saying.
"It is clear as day that even if the opposition is armed to the teeth, it will not defeat the Syrian army, and there will simply be slaughter and mutual destruction for long, long years," he added.
Despite its pro-Assad tone, some diplomats have said Moscow has grown increasingly frustrated with Damascus and its failure to end the uprising.
"Russia believes regime change in Syria would result in an Islamist regime after a great deal of bloodshed," one senior diplomat told Reuters.
Syrian Foreign Minister Walid al-Moualem is due in Moscow for talks on April 10, Russia's Foreign Ministry said.
The opposition Syrian Observatory for Human Rights, a British-based monitor that collates reports from inside Syria, said 58 civilians and 18 soldiers had been killed on Tuesday.
In Homs province on Wednesday, seven people were killed during clashes, the Observatory reported.
Accounts of the violence could not be verified because Syria's government restricts access to independent journalists.