Syrian military forces are poised to enter another northern town, while an increasing number of civilians are fleeing to Turkey to escape the military crackdown on anti-government protesters.

Witnesses and activists said tanks have surrounded the town of Maarat al-Numan, escalating military operations against recent unrest in the region.

Syrian troops remain in control of the nearby flashpoint town of Jisr al-Shughour after pushing into it on Sunday.

Turkish officials say the number of Syrians who have crossed the border to flee the crackdown has swelled to 8,500. Turkish Prime Minister Recep Tayyip Erdogan is to meet with a Syrian envoy on Wednesday to discuss ways to end the turmoil and the tide of refugees into Turkey.

Syria is urging people who fled to Turkey to escape the crackdown in Jisr al-Shughour to return home. The official news agency SANA said that “calm and security” had been restored in the town and surrounding area. It said “all necessary needs” would be provided for the returning refugees, including medical aid and food.

Meanwhile, the United Nations High Commissioner for Human Rights is raising concern about reports of an excessive use of force and the mass detentions of protesters in Syria. Navi Pillay is expected to call for a full investigation into alleged abuses in Syria when she presents her findings to the U.N. Human Rights Council Wednesday.

Also Wednesday, thousands of loyalists to Syrian President Bashar al-Assad staged a rally on the outskirts of Damascus, where they unfurled a huge Syrian flag measuring 2.3 kilometers. Some demonstrators carried pictures of the Syrian leader and shouted, “The people want Bashar Assad.”

Rights activists say about 1,300 civilians and 340 security force members have been killed since the protests against Mr. Assad's government began in mid-March.

Syria has banned most foreign journalists, making it difficult to verify accounts of events.