BEIRUT -- The Syrian army shelled a border town overnight and early Thursday, sparking gunbattles that killed at least eight people, and the government condemned U.S. sanctions targeting President Bashar Assad for the brutal crackdown that has killed more than 850 people.

The violence came hours after the U.S. slapped new sanctions on Assad that for the first time hold the Syrian leader personally accountable for attacks by his security forces. President Barack Obama was expected to use a sweeping Middle East speech on Thursday to sharply defend the sanctions and offer stern words for Assad.

The European Union also is pushing for a second round of European sanctions that would target Assad.

The Syrian government denounced the U.S. measure, calling it "one in a series of sanctions imposed by the U.S. administration against the Syrian people as part of U.S. regional policies serving Israel."

The move "did not and will not affect Syria's independent choices and steadfastness," Syria's state-run news agency said.

The overnight attack on Talkalakh killed at least eight people, bringing the death toll to 34 since the military sealed off the border town Saturday and moved in tanks and troops, two human rights activists told The Associated Press. Syrians fleeing to Lebanon in recent days have described horrific scenes of execution-style murders and bodies in the streets in Talkalakh.

Syria has banned foreign journalists and prevented coverage of the conflict, making it nearly impossible to independently verify accounts coming out of the country or to gauge the strength of the unprecedented protest movement in one of the most authoritarian regimes in the Middle East.

Talkalakh, a town of some 70,000 people near the border with Lebanon, is known to be a smuggling area where many residents are armed. It has been a hotbed of dissent during the two-month uprising against Assad's autocratic rule.

One activist, who asked that his name not be used for fear of reprisals from the government, said there were heavy exchanges of fire between security forces and armed civilians. He added that 19 soldiers also have died in the town.

The second activist, Mustafa Osso, said he could not confirm the accounts of armed resistance from civilians. He said his group was investigating reports that security forces were shooting at soldiers who refused to fire on civilians.

The U.S. action marks the first time that sanctions would hold Assad personally accountable for actions of his security forces.

"The recent events in Syria, we believe, prove that the country cannot go back to the status quo ante," said White House press secretary Jay Carney. "Syria's future will only be secured by a government that reflects the popular will of its people."

But longtime ally Russia threw its support behind Assad. Russian President Dmitry Medvedev said Wednesday that Assad must be given a chance to fulfill his reform promises and warned against foreign interference in the country.