Four Palestinians were killed and 37 wounded in shootings late Friday and early Saturday, threatening the calm that has accompanied a power-sharing deal between Islamic Hamas militants and the rival Fatah Party. The violence began shortly before midnight Saturday when Mohammed Ghelban, a 28-year-old commander from Hamas's military wing, was killed in a drive-by shooting outside of his home. A 22-year-old man from a Fatah family, Hazem Karouah, was killed several hours later, as was 75-year-old Ismail Sabah, who was caught in the line of fire. A fourth woman, 27-year-old Ghada Karouah, died of gunshot wounds later in the day. Four of the wounded were in critical condition, hospital officials said. In keeping with efforts to maintain the fragile calm, the two factions did not openly blame each other. But in a statement to The Associated Press, Hamas's military wing accused "suspect figures hiding behind the cover of Karouah family" of executing Ghelban. The statement called on the Karouah family "to stop protecting the killers" and said Hamas fighters reserved the right to punish the killer. At least 130 people died in Hamas-Fatah fighting before the two sides signed a power-sharing agreement earlier this month in Mecca, Saudi Arabia. The pact is widely seen in Palestinian territories as the only way to avert civil war. Government spokesman Ghazi Hamad of Hamas denounced the latest violence in a statement to reporters, and accused some groups of "trying to revive the internal conflict through acts of aggression."