Arab states plan to cut commercial ties with President Bashar al-Assad's government and freeze its assets in response to violence in Syria, where activists said 42 civilians and soldiers died on Saturday.

The sanctions, which would plunge Syria deeper into economic crisis and regional isolation, were drawn up by an Arab League economic committee in Cairo on Saturday and need to be ratified by foreign ministers meeting on Sunday before coming into force.

They would also include a travel ban on senior Syrian officials and a halt to commercial flights to the country, according to an Arab League document seen by Reuters.

Dealings with Syria's central bank would be halted, it said, but basic essentials needed by the Syrian people would be exempted from sanctions.

The move follows Syria's failure to let monitors into the country, part of a broader Arab League initiative aimed at ending Assad's eight-month crackdown on protests in which the United Nations says 3,500 people have been killed.

Despite Syria's pledge to withdraw its army from cities and let in monitors, the violence has continued, prompting unusually tough reprisals from the Cairo-based League, stinging rebukes from Turkey and French calls for humanitarian intervention.

Hundreds of people - civilians, soldiers and army deserters - have been reported killed in Syria this month, possibly the bloodiest since the unrest broke out in March inspired by uprisings which overthrew leaders in Tunisia, Egypt and Libya.

The Syrian Observatory for Human Rights said 27 civilians died in Syria on Saturday, most of them shot by security forces in the cities of Homs and Qusayr.

Army deserters killed 12 soldiers in the northern province of Idlib when they attacked a convoy heading for the town of Maarat al-Numan, it said, while the bodies of three soldiers, two of them deserters, were returned to their families.

Damascus, where the Assad family has ruled for 41 years, says regional powers helped incite the violence, which it blames on armed groups targeting civilians and its security forces. Syria has barred most independent media, making it hard to verify accounts from activists or officials.

IRAQ HAS RESERVATIONS

It was not immediately clear how united any Arab embargos against Syria would be in practice.

Iraqi Foreign Minister Hoshyar Zebari said his country would not take part in Saturday's deliberations and said other Arab neighbours of Syria also had reservations about sanctions.

Iraq is a neighbour to Syria and there are interests - there are hundreds of thousands of Iraqis living in Syria and there is trade, he told reporters in Najaf. Lebanon also has the same idea and Jordan too has shown its objection.

Lebanon was one of only two countries to vote against suspending Syria from the Arab League earlier this month.

Foreign Minister Adnan Mansour has said his country would not impose sanctions on Syria, but Prime Minister Najib Mikati said Lebanon would implement Arab League decisions because it is in our interest to be with the Arab consensus.

Syria's economy is already reeling from months of unrest, aggravated by U.S. and European sanctions on oil exports and several state businesses.

Its powerful non-Arab northern neighbour Turkey, a former ally, has now turned against Assad.

It is important that the international community move to resolve this problem and deliver a powerful message to the Syrian government, said Turkish Deputy Prime Minister Ali Babacan, who was invited to attend Saturday's meeting.

The draft document said Arab states would freeze the financing of projects on Syrian territory and Arab central banks would monitor bank transfers and letters of credit to make sure they comply with the sanctions. Remittances sent home by Syrians working abroad would not be blocked.

Babacan said the sanctions must not affect the daily life of Syria's people or threaten basic needs such as access to water.

HUMANITARIAN CORRIDORS

The stepped-up pressure follows a French proposal for humanitarian corridors to be set up through which food and medicine could be shipped to alleviate civilian suffering.

The proposal could link Syrian civilian centres to the frontiers of Turkey and Lebanon, to the Mediterranean coast or to an airport, and enable supply of humanitarian supplies or medicines to people in need.

But United Nations humanitarian coordinator Valerie Amos suggested that setting up humanitarian corridors into Syria or buffer zones on the border could be premature.

At present, the humanitarian needs identified in Syria do not warrant the implementation of either of those mechanisms.

Amos said 3 million people had been affected by the uprising against Assad, and Syria's Red Crescent had sought support to feed 1.5 million people. But the United Nations had been unable to assess comprehensively their needs because many international staff had left since the unrest broke out.

Alongside the mainly peaceful protests, armed insurgents have increasingly attacked military targets in recent weeks. Officials say 1,100 security force members have been killed.

State news agency SANA reported funerals of 22 security force members on Saturday, including six pilots killed in an attack on an air force base between Homs and Palmyra two days earlier which the army blamed on an armed terrorist group.

This confirms the involvement of foreign elements and their support of these terrorist operations in an effort to weaken the fighting capabilities of our forces, the army said on Friday.

The account fits the government narrative that it faces an armed insurrection by troublemakers backed by its enemies, rather than a largely peaceful pro-democracy movement inspired by the Arab Spring revolts which toppled the rulers of Tunisia, Egypt and Libya and may have forced out Yemen's president.

State television showed footage of thousands of people demonstrating in the Mediterranean city of Latakia on Saturday, condemning the Arab League for taking a stance against Syria and chanting in support of Assad.

(Additional reporting by Dominic Evans in Beirut, Patrick Werr and Tom Pfeiffer in Cairo, and Patrick Markey in Baghdad; Writing by Dominic Evans; Editing by Andrew Roche)