Syrian forces killed 11 people on Thursday as the government widened its crackdown on dissent to at least two more areas of the country.
Activists and witnesses said the deaths occurred in Qusair, a town in the central Homs province, after columns of tanks pushed into the town and government forces opened fire.
A second raid took place in the northwestern town of Saraqeb near the Turkish border. The activists said security forces raided homes and arrested at least 70 people.
The new assaults took place despite mounting international pressure against President Bashar al-Assad's crackdown on political dissent.
In Washington, the Obama administration said Syria would be "a better place" without its leader, but has not explicitly called on him to stop the brutal attacks on demonstrators.
The White House said U.S. President Barack Obama and Turkish Prime Minister Recep Tayyip Erdogan agreed during a phone call Thursday on the need for a transition to democracy and an immediate end to the bloodshed in Syria.
U.S. Ambassador to Syria Robert Ford met with Syria's Foreign Minister Walid Muallem Thursday in Damascus. U.S. State Department said Ambassador Ford made clear that Syria is going to face increasing pressure, including more economic sanctions from the U.S. and others, if the violence does not stop.
U.S. Secretary of State Hillary Clinton, when asked why the United States has not yet called for Syria's president to step down, said it was important that it is not just the American voice. In an interview with CBS News Clinton said Washington wants to make sure that other nations add their voices.
On Wednesday, the United States announced new sanctions on Damascus, saying it would freeze U.S. assets of a Syrian bank and mobile phone operator.
Also Wednesday, Britain's deputy ambassador to the United Nations said Syria is carrying out an offensive against its people that is "brutal and unwarranted," but Syria rejected his remarks.
Details of events in Syria are difficult to confirm because the government allows very few foreign news reporters into the country and restricts their movements.
At least 12 people were killed Wednesday in the government crackdown on dissidents.
Some information for this report was provided by AP, AFP and Reuters.