Activists and witnesses say Syrian security forces shot and killed at least 19 people across the country on Friday during anti-government protests. The reports say protesters were killed in at least six Syrian cities, including Hama, Homs and Aleppo, as well as the suburbs of Damascus.

Forces loyal to Syrian President Bashar al-Assad have intensified their violent suppression of opposition protests during the past week, despite growing international condemnation.

On Friday, U.S. Secretary of State Hillary Clinton urged countries giving Syria economic and political support to “get on the right side of history.” She also called on countries to stop buying Syrian oil and gas.

Clinton says she is continuing diplomatic talks aimed at putting political pressure on Mr. Assad's government. She again insisted the Syrian president has “lost the legitimacy to lead,” but still stopped short of calling for Mr. Assad to step down, saying that calls for his removal should be part of an international effort.

Meanwhile, Turkish President Abdullah Gul called on Mr. Assad to implement reforms before it is too “late.” Turkish media reports relayed Mr. Gul's comments on Friday.

The Syrian government has defended its crackdown, saying it is combating armed gangs and terrorists. On Friday, state-run news reports said “armed groups” with “snipers” had opened fire “randomly” in a Damascus suburb and two other areas, killing three law enforcement officers and two civilians.

The United Nations Security Council plans to meet next Thursday to consider further action against the Syrian government. Earlier this month, the Security Council issued a statement condemning Syria for attacks on civilians and widespread human rights violations,

While the statement called for those responsible on “all sides” to be “held accountable,” it contains no enforceable demands or sanctions and does not seek to have Syrian leaders referred to the International Criminal Court, as opposition groups have demanded.

U.S. officials have estimated that more than 2,000 people have been killed in the months-long effort to suppress dissent in the country.

Details of events in Syria are difficult to independently verify because the government allows very few foreign news reporters into the country and restricts their movements.