The U.N. chief told Bashar al-Assad on Sunday to stop killing your people and the Syrian leader offered an amnesty for crimes committed during a 10-month-old revolt against him.
Arab League foreign ministers will meet next Sunday to discuss the future of a monitoring mission sent last month to check if Syria is respecting an Arab peace plan.
Assad's violent response to the uprising has killed more than 5,000 people, by a U.N. count. The Syrian authorities say 2,000 members of the security forces have also been killed. At least 25 civilians and soldiers were reported killed on Sunday.
Today, I say again to President Assad of Syria: stop the violence, stop killing your people. The path of repression is a dead end, U.N. Secretary-General Ban Ki-moon told a conference in Lebanon on democratic transitions in the Arab world.
Assad's amnesty will run to the end of January, covering army deserters and people who possessed illegal arms or had violated laws on peaceful protest, the state news agency SANA said.
Syria's Addounia television said Arab monitors discussed the amnesty with Damascus police on Sunday.
Opponents of Assad said the amnesty was meaningless because most detainees were held without charge in secret police or military facilities with no due process or legal documentation.
The problem is not those who have reached trial or have been sentenced to terms in civic jails but those who are imprisoned and we don't know where they are or anything about them, said Kamal Labwani, who was freed last month after six years as a political prisoner and is now in Jordan.
The Arab League's Syria committee, whose Qatari chairman has said the observer mission has failed to staunch the bloodshed, will discuss a report by the monitors on Friday, Egypt's MENA news agency said.
The Cairo-based League will not send any more monitors to Syria before the Arab foreign ministers meet next Sunday, MENA said.
Anti-Assad protests began in March inspired by a wave of popular anger against autocratic rulers sweeping the Arab world.
Assad has issued several amnesties since the start of protests, but opposition groups say thousands of people remain behind bars and many have been tortured or abused.
The Avaaz campaign group said on December 22 at least 69,000 people had been detained since the start of the uprising, of whom 32,000 had been released.
Freeing detainees was one of the terms of an Arab League peace plan which also called for an end to bloodshed, the withdrawal of troops and tanks from the streets and a political dialogue.
The movement to end more than four decades of Assad family rule began with largely peaceful demonstrations, but after months of violence by the security forces, army deserters and insurgents started to fight back, prompting fears of civil war.
An opposition group said five textile workers were killed when a bomb hit their bus in the northern province of Idlib on Sunday. SANA blamed the attack on an armed terrorist group.
SANA also said six soldiers killed by such groups were buried in the rebellious central city of Homs.
Sunday's civilian death toll in Homs rose to 11, the British-based Syrian Observatory for Human Rights reported. It said three people were also killed in random shooting by security forces in the town of Qarqas in Quneitra province.
Live footage aired from Zabadani, a rebel-held town attacked by tanks and troops on Friday, showed Arab League monitors walking among several thousand demonstrators in the main square, where a large Christmas tree stands.
God is greater than the oppressor, protesters shouted, while others held a large white and green flag that was Syria's national emblem before Assad's Baath party took power.
Qatar's emir, once a friend of Assad, has said Arab troops may have to step in to halt bloodletting that has gone on unchecked despite the presence of Arab League monitors sent to find out if the Arab peace plan agreed last year is working.
Asked if he was in favour of Arab nations intervening in Syria, Qatari Emir Sheikh Hamad bin Khalifa al-Thani told the U.S. broadcaster CBS: For such a situation to stop the killing ... some troops should go to stop the killing.
The emir, whose country backed last year's NATO campaign that helped Libyan rebels topple Muammar Gaddafi, is the first Arab leader to propose Arab military intervention in Syria.
There is little Western appetite for any Libya-style intervention and an Arab representative to the Cairo-based League said it had received no formal proposal for such action.
There is no official suggestion to send Arab troops to Syria at the current time, he said. There has been no Arab or a non-Arab agreement on a military intervention in Syria.
China and Russia have blocked any action against Syria by the U.N. Security Council. The United States, the European Union and the Arab League have announced economic sanctions, although it is not clear if the Arab measures have been implemented.
Turkey, whose foreign minister was in Beirut at the weekend, has also imposed sanctions on Syria after the violence prompted it to turn against a neighbour it had once courted assiduously.
British Foreign Secretary William Hague said he hoped more sanctions on Syria could be agreed in the next 10 days or so, referring to a January 23 meeting of EU foreign ministers.
In an interview with Sky News television, Hague also questioned the sincerity of Assad's amnesty offer and said he hoped the Arab League would refer Syria to the United Nations if the monitoring mission failed to halt the violence.
He dismissed the idea of a no-fly zone in Syria, saying there was no chance for now of Security Council approval for such action, which was not necessarily appropriate anyway.
It's not primarily by flying aircraft that the Assad regime is repressing its people, Hague said.
(Additional reporting by Khaled Yacoub Oweis in Amman, Dominic Evans in Beirut, Yasmine Saleh in Cairo and Adrian Croft in London; Writing by Alistair Lyon; Editing by Rosalind Russell)