Newsbeat's guide to... Syria
At least 60 people are reported to have been killed in Syria on Sunday - a day after the Arab League suspended its monitoring mission in the troubled country.
Activists say at least 26 died in the capital, Damascus, after government tanks attacked rebel-held areas.
They say it's the fiercest fighting there since the uprising began 10 months ago.
On Saturday, the Arab League said a spike in violence meant it was temporarily pulling out of the country.
The league wants Syria's President Bashar al-Assad to hand over power to his deputy and form a national unity government with the opposition.
But the government has rejected the plan as "interference".
Protests in Syria have been going on since March 2011.
The authorities have been internationally criticised for responding to the unrest with military force.
The government claims it is fighting "terrorist" groups and says 2000 members of the security forces have been killed.
What do the protesters want?
The demonstrations began shortly after anti-government uprisings in Tunisia and Egypt in mid-March.
A group of teenagers spray-painted a revolutionary slogan on a wall in the southern city of Deraa.
They were arrested and soon the unrest spread to other areas.
Protesters started by calling for democracy and freedom in what is one of the most repressive countries in the Arab world.
For example, there are emergency laws which allow people to be arrested without warrants and imprisoned without trials.
Syria's president has promised some changes but protesters say the killing is continuing so they want him to step down.
Mr Assad has described protesters as terrorists who need to be removed.
The UN says 5,000 people have died - mainly protesters but also members of Syria's security forces - while thousands more have been injured.
Why is there no foreign military action as in Libya?
For decades Syria has been among the most stable countries in the Middle East.
It is a major player in the region because of where it's positioned, unlike Libya which is more isolated.
A military attack on Syria would cause knock-on effects in neighbouring countries.
It may mobilise militant groups like Hezbollah in Lebanon, Hamas in the Gaza Strip and other more radical Palestinian groups opposed to peace with Israel.
Syria is also strongly supported by Iran - a country considered hostile by the US, Israel and Saudi Arabia - which could potentially draw those powers into a dangerous Middle Eastern conflict.
President Bashar al-Assad has warned any foreign military action will turn Syria "into another Afghanistan".
Is there any support for the president inside Syria?
Syria is a mixed country of 21 million people with a large Sunni Muslim majority and minorities of Christians, Alawites and Jewish people.
Mr Assad belongs to the Alawaite sect.
He's supported by many people from the upper classes and minority groups.
The protests against him have mainly been in Sunni populated areas.
What action has been taken so far against Syria?
The Arab League - which is a group of 22 Arabic speaking countries - sent in 165 people to monitor the situation in December 2011.
They agreed a deal with Syrian officials to scale down the violence.
But they've accused the government of killing hundreds of civilians since the monitoring mission began.
They want the Syrian authorities to form a national unity government with the opposition - which has been refused.
The league temporarily pulled out of the country on 28 January, blaming an upsurge in violence.
The UN Security Council will now consider whether a tough international resolution can add more pressure on the regime.