US President Barack Obama plunged straight into the Middle East conflict on his first day in office on Wednesday, calling four regional allies including the Palestinian president, and making the move to ask former Northern Ireland peacemaker George Mitchell to serve as Middle East envoy. Obama called Egyptian President Hosni Mubarak, Israeli Prime Minister Ehud Olmert, Jordan's King Abdullah II and Palestinian President Mahmoud Abbas. “He used this opportunity on his first day in office to communicate his commitment to active engagement in pursuit of Arab-Israeli peace from the beginning of his term, and to express his hope for their continued cooperation and leadership,” White House press secretary Robert Gibbs said. Gibbs said Obama “emphasized his determination to work to help consolidate the cease-fire by establishing an effective anti-smuggling regime to prevent Hamas from rearming,” and by working with Palestinian leadership to help create “a major reconstruction effort for Palestinians in Gaza.” In his phone calls, Gibbs said, Obama pledged that his government would do its share to make those efforts successful and work with international partners “as they fulfill their responsibilities as well.” The White House described the calls as warm in nature.Abbas's spokesman said Obama assured the Palestinian president that he intended “to work with him as partners to establish a durable peace in the region.” The Jordanian Embassy in Washington said that King Abdullah “stressed the importance of early US engagement in serious and effective peace negotiations” to solve the Palestinian-Israeli dispute quickly. Obama inherits the aftermath of a conflict that roiled the Middle East anew and dogged the final days of the Bush administration: An Israeli offensive that ravaged Gaza and left some 1,300 Palestinians dead, at least half of them civilians, according to estimates. Obama told Abbas that he was the first foreign leader he called since taking office, said Palestinian spokesman Nabil Abu Rudeina. “We were not expecting such a quick call from President Obama but we knew how serious he is about the Palestinian problem,” said Yasser Abed Rabbo, an Abbas aide. Israeli Prime Minister Ehud Olmert briefed Obama on the situation in the Gaza Strip during a separate phone call, Olmert's office said. The last Israeli troops left the Gaza Strip before dawn Wednesday. A source close to the administration said that Obama has asked Mitchell, 75, to serve as Middle East envoy, and that an announcement could be made shortly.