WASHINGTON - President Barack Obama Wednesday dived into the treacherous diplomacy of the Middle East, promised a new era of ethical politics and froze the salaries of top staff in a frenetic first day in office.
The new president, determined to honor his vow to forge fundamental political change, also called in top military and economic chiefs to confront the string of dark crises he inherited from former president George W. Bush.
At the start of his first full day as president, Obama spent a few poignant moments alone in the Oval Office, reading a private letter left for him by his predecessor, when he ceded power on Tuesday.
Then, flexing his diplomatic muscles in the Middle East for the first time, Obama telephoned Palestinian leader Mahmud Abbas, Egyptian President Hosni Mubarak, Israeli Prime Minister Ehud Olmert and King Abdullah II of Jordan.
Obama "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," his spokesman Robert Gibbs said in a statement.
The new president has also asked former Northern Ireland peacemaker and senator George Mitchell to serve as Middle East envoy, a source close to the administration said.
Top Obama aides meanwhile said that the widely expected executive order from the new president to start closing the Guantanamo Bay "war on terror" prison camp would not come Wednesday, though was due shortly.
Obama also sought to make a splash on his ambitious domestic agenda, in line with a promise to purge the influence peddling and corruption staining US politics by signing a string of executive orders dealing with political ethics.
"Let me say it as simply as I can. Transparency and the rule of law will be the touchstones of this presidency," he said, at a swearing-in ceremony for senior staff members.
The orders tightened rules on contact between lobbyists and members of the government and restricted contact between former administration members with ex-colleagues when they leave public service.
With many Americans feeling the economic pinch, Obama also clamped a salary freeze on top staff earning over more than 100,000 dollars a year.
"During this period of economic emergency, families are tightening their belts, and so should Washington," Obama said.
Later, Obama met his top economic advisors for an update on the 800 billion dollar plus stimulus bill he is trying to push through the US Congress.
He was also set to call in the Chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, Defense Secretary Robert Gates and other military advisors at a National Security Council meeting, including war commander David Petraeus.
"The president is going to get an update about what is going on in Iraq," said Gibbs.
"He will ask for planning to redeploy combat troops within 16 months."
Earlier, still basking in the euphoria surrounding his inauguration as the first black president, Obama went to Washington's National Cathedral to hear prayers for his administration.
The Obamas sat in a high-powered front pew alongside Vice President Joseph Biden and his wife Jill and former president Bill Clinton and Hillary Clinton.
"Oh God, we ask that your hand of wisdom, grace, courage, and protection will be upon, underneath, and around our 44th president, President Barack Obama," prayed Reverend Otis Moss, a renowned pastor from Cleveland, Ohio.
On Capitol Hill, Obama's cabinet nominations made slow progress.
His pick for Treasury Secretary Timonty Geithner, faced a grilling in his confirmation hearing from Republicans concerned about his failure to pay 34,000 dollars in past tax returns.
Republicans meanwhile frustrated Democratic leaders of the Senate Judiciary committee by forcing them to delay a vote on the nomination of Eric Holder to be attorney general for a week.
The opposition party has expressed concerns that Holder will sign on to prosecutions of interrogators who carried out controversial Bush administration "war on terror" interrogation tactics.
As he waded into tough policy work, Obama had a few more moments to reflect on his achievement of winning the White House as the first black president.
He and wife Michelle stood in the ornate White House Blue Room and met more than 200 people who won passes to an "Open House."
"There's Barack! There's Barack!" cried elderly Philadelphia woman Audrey Thornton as she glimpsed the new president through an open door as she was rolled through the lobby in a wheelchair on the way to the event.