Syrian forces shot dead six protesters on Friday despite President Bashar al-Assad's pledge

Syrian forces shot dead six protesters on Friday despite President Bashar al-Assad's pledge that his military crackdown on dissent was over, as thousands marched across the country spurred on by U.S. and European calls for him to step down.

The shooting broke out on Friday in the southern province of Deraa where the five-month uprising against Assad erupted in March, triggering a brutal response in which U.N. investigators say his forces may have committed crimes against humanity.

"We have names of four confirmed dead protesters in Inkhil and reports of heavy firing on demonstrations by the security forces across Deraa's countryside," Abdallah Aba Zaid, a prominent local activist, told Reuters.

Thamer Jahamani, a lawyer, said two other people were killed when security forces opened fire on a demonstration in the town of Hirak. Dozens of people were wounded, he said.

The main midday Muslim prayers held on Friday have been a launch pad for huge rallies across Syria and have seen some of the heaviest bloodshed, with 20 people killed last week in defiant protests chanting: "We kneel only to God."

Assad, from the minority Alawite sect in the majority Sunni Muslim nation, told U.N. Secretary-General Ban Ki-moon this week that military and police operations had stopped, but activists say his forces are still shooting at protesters.

"Maybe Bashar al-Assad does not regard police as security forces," said a witness in Hama, where security force fired machine guns later on Thursday to prevent a night time protest.

Syrian state television said gunmen attacked a police post in Deraa province, killing a policeman and a civilian, and wounding two others.

Syria has expelled most independent media since the unrest began, making it difficult to verify reports of violence in which the United Nations says 2,000 civilians have been killed. Authorities blame terrorists and extremists for the bloodshed and say 500 soldiers and police have been killed.

SNIPERS ON ROOF

Internet footage of Friday's protests suggested that although widespread they were smaller than at their peak in July, before Assad sent tanks and troops into several cities.

A doctor in Zabadani, 30 km (20 miles) northeast of Damascus, said army vehicles were in the town and snipers were on the roof to prevent crowds marching.

Protesters from Syria's Sunni majority resent the power and wealth amassed by some Alawites, who adhere to an offshoot of Shi'ite Islam, and want Assad to quit, the dismantling of the security apparatus and the introduction of sweeping reforms.

The violent repression prompted coordinated calls from the United States and European Union on Thursday for Assad to step down and Washington imposed sweeping new sanctions on Syria, which borders Israel, Lebanon and Iraq and is an ally of Iran.

There is no immediate obvious alternative leader to Assad although the disparate opposition, persecuted for decades, has gained a fresh sense of purpose as popular disaffection has spread across the country.

President Barack Obama ordered Syrian government assets in the United States frozen, banned U.S. citizens from operating or investing in Syria and prohibited U.S. imports of Syrian oil products.

"The future of Syria must be determined by its people, but President Bashar al-Assad is standing in their way," Obama said. "His calls for dialogue and reform have rung hollow while he is imprisoning, torturing and slaughtering his own people."

Diplomats said the European Union could decided to toughen sanctions to match the U.S. measures, including a ban on oil imports. Syria exports over one third of its 385,000 barrels per day oil production to Europe.

Adding to international pressure, U.N. investigators said Assad's forces had committed violations that may amount to crimes against humanity. The United Nations plans to send a team to Syria on Saturday to assess the humanitarian situation.

Simultaneously, European Union foreign policy chief Catherine Ashton called on Assad to step aside and said the EU was preparing to broaden its own sanctions against Syria.

The United States, Britain and European allies said on Thursday they would draft a U.N. Security Council sanctions resolution on Syria.

But Russia, which has resisted Western calls for U.N. sanctions, said on Friday it also opposed calls for Assad to step down and believed he needs time to implement reforms.

"We do not support such calls and believe that it is necessary now to give President Assad's regime time to realize all the reform processes that have been announced," Interfax news agency quoted a foreign ministry source as saying.

SANCTIONS IMPACT

Despite the dramatic sharpening of Western rhetoric, there is no threat of Western military action like that against Libya's Muammar Gaddafi, meaning Assad's conflict with his opponents seems likely to grind on in the streets.

It may also take time for the diplomatic broadside, backed by the new sanctions, to have an impact on the 45-year-old president who took power when his father President Hafez al-Assad died 11 years ago after three decades in office.

Assad has so far brushed off international pressure and survived years of U.S. and European isolation following the 2005 assassination of Lebanese statesman Rafik al-Hariri, a killing many Western nations held Damascus responsible for.

But Syria's economy, already hit by a collapse in tourism revenue, could be further damaged by Obama's announcement. U.S. sanctions will make it very difficult for banks to finance transactions involving Syrian oil exports.

It will make it also challenging for companies with a large U.S. presence, such as Shell, to continue producing crude in Syria -- although the impact on global oil markets from a potential shutdown of Syria's 380,000 barrels per day oil industry would be small compared to that of Libya.

Assad says the protests are a foreign conspiracy to divide Syria and said last week his army would "not relent in pursuing terrorist groups."

U.N. investigators said on Thursday Syrian forces had fired on peaceful protesters, often at short range. Their wounds were "consistent with an apparent shoot-to-kill policy."