The Palestinian security forces executed on Sunday four men convicted of murder, three of them by hanging, an Interior Ministry spokesman said. The executions, the first since 2001, are part of the Palestinian Authority's attempt to rein in lawlessness that has plagued the West Bank and Gaza Strip during the past four years of fighting with Israel, said spokesman Tawfiq Abu Housa. The four men executed were convicted of murder and sentenced to death by Palestinian courts, Abu Housa said. Palestinian leader Mahmoud Abbas signed the execution orders on Saturday, he added. Three of the men were hanged and one was killed by a firing squad, The Associated Press reported. "There is a new policy of enforcing the law to face and fight the chaos and lawlessness in the Palestinian territories," Abu Housa said.