Syrian warplanes bombed rebel positions on the outskirts of the central city of Homs on Tuesday to try to break a siege of an army base housing dozens of soldiers, opposition activists said.Two rebels were killed and 10 wounded at al-Mubarkiyeh, a village 6 km (4 miles) south of Homs, where rebels have besieged a compound guarding a tank maintenance facility, they said.Opposition sources said the facility had been used to shell Sunni Muslim villages near the Lebanese border.There was no word on Syrian army casualties in the fighting, which followed a failed four-day truce proposed by peace envoy Lakhdar Brahimi to mark the Eid al-Adha Muslim holiday.The truce lasted only a few hours and Eid al-Adha ended on Monday with a wave of air strikes on Sunni regions where rebels have slowly made gains. Clashes raged on across the country."The warplanes hit al-Mubarkiyeh five times this morning. Army bulldozers had already razed the village in March,” said activist Nader al-Husseini by telephone from near the area.Syria’s military, stretched thin by the struggle to keep control, has made increasing use of air power against opposition areas, including those in the main cities of Damascus and Aleppo. Insurgents lack eff