Deraa protesters chanted slogans urging people in Damascus, which has seen fewer demonstrations than rural protest centres, to follow their lead. "People of Damascus, here in Deraa we toppled the regime," they chanted.
Protests also erupted in western coastal cities and eastern provinces near Iraq. Syrian troops swept to the northern border with Turkey on Thursday, prompting another 1,500 refugees to flee across the frontier into camps which Turkish officials say now host more than 11,000 refugees.
Syrian television said on Friday army units were "completing their deployment" in border villages. It said there had been no casualties during the operation and that soldiers were greeted with traditional welcomes of flowers and rice by residents.
Assad's repression of the protests, in which Syrian rights groups say more than 1,300 civilians have been killed, has triggered Western condemnation and a gradual escalation of U.S. and European Union economic sanctions against Syrian leaders.
Syrian authorities blame Islamist militants and armed gangs for killing more than 200 police and security personnel.
On Friday the European Union announced extended sanctions against Syria, including against three commanders of Iran's Revolutionary Guard accused of helping Damascus curb dissent. Syria denies Iran has played any role in tackling the unrest.
Four Syrian officials were also targeted, bringing to 34 the number of individuals and entities on the list which already includes Assad and his top officials.
Despite strong rhetoric among against Assad from Western leaders, there has been no suggestion they plan to go beyond economic sanctions to tougher action such as the military intervention launched against Libyan leader Muammar Gaddafi.
The United States, which has also imposed targeted sanctions on Syrian officials, said a reported Syrian army move to surround and target the town of Khirbat al-Joz just 500 metres (yards) from the Turkish border was a worrying development.
"Unless the Syrian forces immediately end their attacks and their provocations that are not only now affecting their own citizens but (raising) the potential of border clashes, then we're going to see an escalation of conflict in the area," U.S. Secretary of State Hillary Clinton said.
The crackdown has caused a crisis in Assad's once-warm relations with Turkey, which has become strongly critical.
Clinton said she had discussed the situation with Turkish Foreign Minister Ahmet Davutoglu, and President Barack Obama had discussed it with Turkish Prime Minister Tayyip Erdogan.
Davutoglu, who said Erdogan would speak to Assad on Friday, talked to Syrian Foreign Minister Walid al-Moualem on Thursday and Ankara summoned the Syrian ambassador.
In an apparent easing of Ankara's criticism, Davutoglu said Assad's speech contained "positive elements in it as signals of reform," but said it was important that action followed.
At the border, only a few Syrian troops were visible on Friday, some occupying a building on a hill overlooking the border, directly across from the Turkish village of Guvecci.
Three Syrian soldiers were manning a sand-bagged machinegun post on top of a house in the Syrian border village of Khirbat al-Joz. Camps on the Syrian side of the border fence appeared deserted and no more refugees were crossing.
The United States has steadily sharpened its rhetoric toward Assad, saying he is losing credibility and must either implement promised reforms or get out of the way.
Protests have grown in northern areas following military assaults on towns and villages in the Jisr al-Shughour region of Idlib province, west of Aleppo, that sent more than 10,000 people fleeing across the 840-km (520-mile) border with Turkey.
Syrian television said hundreds of people were heading back to Jisr al-Shughour. A refugee who said he was at Yayladagi camp said on Thursday a delegation of notables from the city told people it was safe to go back, but that refugees told them there would be "no return until the fall of the (Assad) regime."
Syria, a mostly Sunni nation of 20 million with Kurdish, Alawite and Christian minorities, is vulnerable to sectarian tensions. Assad belongs to the Alawite sect, an offshoot of Shi'ite Islam, and his opponents say he increasingly relies on loyalist Alawite troops and irregulars known as 'shabbiha'.