Date: Apr 29, 2011 Source: Associated Press   Latest developments in Arab world's unrest SYRIA Syrian army units clash with each other over following President Bashar Assad's orders to crack down on protesters in Daraa, a besieged city at the heart of the uprising, witnesses and human rights groups say. More than 450 people have been killed across Syria — about 100 in Daraa alone — and hundreds detained since the popular revolt against Assad began in mid-March, according to human rights groups. ___ LIBYA Moammar Gadhafi's forces shell civilian areas in the rebel-held city of Misrata, killing 10 people. Regime supporters and opponents battle on another front in western Libya for control of a crossing point along the Tunisian border, killing refugees as they flee. ___ YEMEN Yemeni government opponents clash with police in the southern province of Aden, as tens of thousands of protesters rally nationwide to denounce a deadly government crackdown and demand the president's ouster. The street clashes were triggered by a bomb attack by an unknown armed group on a checkpoint in the provincial capital, Krater, and signal the rapid deterioration of security. ___ BAHRAIN A military court in Bahrain sentences four Shiite protesters to death after convicting them of killing two policemen during anti-government demonstrations last month, state media says.