WASHINGTON (AP) - Facing the enormous task of assembling a new government, President-elect Barack Obama on Thursday closeted himself in Chicago for his first presidential-style intelligence briefing before moving into the White House in 10 weeks.

He planned his first public appearance since his presidential victory for Friday - a meeting with economic advisers to discuss the nation's financial troubles, which Americans listed as their top concern on election day. Obama plans to talk to the news media Friday afternoon after the meeting, aides said.

He and his wife, Michelle, will visit the White House on Monday at the invitation of President George W. Bush, aides said.

His new government faces massive challenges both at home and abroad, as evidence made clear on the first days after his historic victory over Republican John McCain in Tuesday's election.

The U.S. stock market greeted his elevation to the pinnacle of American power by plunging nearly 500 points Wednesday on more dire news about an economy in the throes of its worst crisis since the 1930s Great Depression. It fell further on Thursday.

Meanwhile, the Kremlin sounded off as well, with President Dmitry Medvedev declaring: “Mechanisms must be created to block mistaken, egoistical and sometimes simply dangerous decisions of certain members of the international community” - an apparent reference to the United States under Bush.

Medvedev issued the stark challenge even as he threatened to erect missiles along the Polish border if the Obama administration were to go forward with plans laid out by the Bush administration to create a missile shield in the Eastern Europe.

On Thursday, Iranian President Mahmoud Ahmadinejad congratulated Obama - the first time the country's leader has offered such wishes to a U.S. president-elect since the 1979 Islamic Revolution.

Ahmadinejad congratulated the Democrat on “attracting the majority of voters in the election.” The text of the note was carried by the official IRNA news agency.

In the message, Ahmadinejad also said he hoped Obama will “use the opportunity to serve the (American) people and leave a good name” during his term in office.

Iran and U.S. have no formal diplomatic relations since 1979 and the hostage drama when militant Iranian students held 52 Americans captive 444 days.

The Associated Press, meanwhile, declared Obama the winner in North Carolina on Thursday, a symbolic triumph in a state that hadn't voted for a Democrat in more than a generation.

North Carolina's 15 electoral votes brings Obama's total to 364 - nearly 100 more than necessary to win the White House. Missouri is the only state that remains too close to call.

Obama's win in North Carolina was the first for a Democratic presidential candidate since Jimmy Carter won the state in 1976.

The president-elect was quick out of the starting blocks Wednesday, calling on Rep. Rahm Emanuel, a fellow Chicago politician and veteran of the Bill Clinton White House, to serve as his chief of staff.

Emanuel told a Chicago television station he was honored to be considered and has since accepted the position as chief of staff.

Other White House officials were being lined up, including Robert Gibbs as the likely pick for press secretary, said several Obama aides. Gibbs has been Obama's longtime spokesman and confidant and was at Obama's side from his 2004 Senate campaign through the long days on the presidential campaign trail.

Obama planned to stay home through the weekend, with a blackout on news announcements so that he and his staff can get some rest after a grueling campaign and the emotional rush of their win Tuesday night. He is planning a trip to Hawaii in December to get away with his family before their move to the White House - and to honor his grandmother, who died Sunday at her home there.

In offering the post of White House chief of staff to Emanuel, Obama turned to a fellow Illinoisan with a far different style from his own, a man known for his bluntness as well as his single-minded determination.

Emanuel was a political and policy aide to Clinton before he turned to investment banking. He then won a Chicago-area House seat six years ago. In Congress, he moved quickly into the leadership. As chairman of the Democratic campaign committee in 2006, he played an instrumental role in restoring his party to power after 12 years in the minority.

Emanuel maintained neutrality during the long primary battle between Obama and Sen. Hillary Rodham Clinton, not surprising given his long-standing ties to the former first lady and his Illinois connections with Obama.

By Steven R. Hurst - AP Writer