Assad regime attacks border areas, 35 dead Syrians protest against President Bashar Assad, in Yabroud near Damascus last week. More than 7,600 people have been killed in violence across Syria since anti-regime protests erupted last March, the Syrian Observatory for Human Rights has said. DAMASCUS, Syria, March 6 (UPI) -- Syrian opposition groups said at least 35 people were killed Tuesday by government forces attacking an escape route to Lebanon. The Local Coordination Committees of Syria said 23 of the dead were in the opposition stronghold of Homs, CNN reported. Syrian forces attacked a bridge on the Orontes River near the border with Lebanon, the Syrian Observatory for Human Rights said. Dana Suleiman, a spokesman for the U.N. High Commissioner for Refugees in Beirut, said at least 2,000 Syrians have fled into Lebanon since Sunday. U.S. Gen. James Mattis, head of the U.S. Central Command, told a Senate Armed Services Committee hearing President Bashar Assad's forces remain viable. "He will continue to employ heavier and heavier weapons on his people," Mattis said. I think it will get worse before it gets better. Meanwhile, Syria agreed to let the top U.N. relief official and newly designated U.N.-Arab League envoy Kofi Annan visit. Valerie Amos, the U.N. undersecretary-general for humanitarian affairs and emergency relief, said the Assad regime gave her permission to visit Syria for three days starting Wednesday. It was helping two areas of the city but was prevented by Syrian troops from entering the devastated Baba Amr neighborhood, held by rebels for several months before regime forces drove them out Thursday after nearly four weeks of relentless shelling, the ICRC said. Amos said she planned to leave Damascus Friday. At the same time, Syrian security forces widened their campaign to crush opposition, activists said.