Washington  - US President Barack Obama ended an extraordinary first full day in office by taking the oath of office for a second time, a curious distraction as he set a vigorous tone Wednesday for his new administration.

Obama met with economic advisers and military commanders, mapping out new strategies to address the US economic meltdown and ordering his generals to draw up plans for an eventual withdrawal of combat forces from Iraq.

He suspended military tribunals at the Guantanamo Bay detention facility - a step toward closing the much-debated prison camp - and revamped ethics rules, promising a "new era" of transparency and adherence to the rule of law.

Obama telephoned the leaders of Egypt, Israel, Jordan and the Palestinian Authority, promising to engage from the start of his term in a push for progress on the Middle East conflict.

When it was all over, Obama summoned Supreme Court Chief Justice John Roberts to the White House to deliver the oath of office for a second time as the country's 44th president.

Roberts had erred on one word during Tuesday's inaugural ceremony on the Capitol steps, causing Obama to hesitate and fumble his own words during the historic moment.

Greg Craig, the administration's top lawyer, said in a statement that the second swearing-in was held out of an "abundance of caution."

Obama's actions came as the US Senate voted overwhelmingly to confirm Hillary Clinton as secretary of state. She was due to arrive at the State Department for a welcome ceremony Thursday morning, a spokesperson said.

The Senate Foreign Relations Committee voted Wednesday to approve Susan Rice as the next US ambassador to the United Nations, sending her nomination to the full Senate, which must approve all cabinet members and other political appointees.

Other key nominations were moving more slowly. A vote on attorney general-designee Eric Holder was delayed for a week by Republicans on the Senate Judiciary Committee, while Obama's choices for the Treasury and Transportation departments faced tough confirmation hearings Wednesday and have yet to reach the voting stage.

Treasury-designee Timothy Geithner, if confirmed, would become the face of Obama's efforts to stabilize the country's contracting economy and crumbling financial system. He promised swift and "forceful" action to address the economic crisis and touted the 825- billion-dollar stimulus package making its way through Congress.

But he faced tough questions from members of the Senate Finance Committee over his failure to pay 34,000-dollars in pension taxes over a four-year period while he was working for the International Monetary Fund.

Geithner is still likely to be confirmed next week, but the delay meant Obama's full economic team was not in place for Wednesday's first meetings.

Continuing populist themes from his presidential campaign, Obama invited 200 ordinary people to a so-called open house at the White House. The group was chosen from people who responded to an e-mail from Obama's inaugural committee offering the privilege.

Obama, 47, began the day with 10 minutes alone in the Oval Office, where outgoing president George W Bush had left him the traditional letter, in an envelope marked "To: #44, From: #43," Obama's press secretary Robert Gibbs said.

Obama and his wife, Michelle, attended a traditional interfaith prayer service later in the morning at Washington's National Cathedral that included leaders from four different religions.

Just hours after his inauguration, Obama ordered prosecutors to seek delays in all military tribunal proceedings at Guantanamo Bay so his administration can review the cases and decide how to move forward.

A military judge later granted a motion by prosecutors to suspend proceedings for 120 days against five alleged plotters of the September 11, 2001, terrorist attacks, including purported mastermind Khalid Sheikh Mohammed. Another judge suspended the case against Omar Khadr, a 21-year-old Canadian citizen accused of killing a US soldier in Afghanistan in 2002.

Obama is expected to issue a directive Thursday that the Guantanamo facility be closed within one year, US media reported.

Among his first acts in office, Obama signed a series of ethics directives that clamped down on the influence of lobbyists and directed agencies to make federal documents more accessible to the public and media.

"Transparency and the rule of law will be the touchstones of this presidency," Obama said during a signing ceremony, which also included the swearing-in of Obama's senior White House staff.

In a nod to the economic struggles of ordinary families in the US, Obama froze the salaries of senior White House staff. Together, he hoped the measures would help "restore trust" in the US government. (dpa)