Argentina's president has said that she would refuse to comply with a U.S. judge's order to pay $1.5 billion to winners of a decade-long legal battle over defaulted debt after the U.S. Supreme Court refused to hear her government's final appeal.

Delivering a nationally broadcast address Monday night, Cristina Fernandez expressed willingness to negotiate with the winners, but said there is simply no way that Argentina can pay the amount in cash, in full, starting just two weeks from now, which is what the U.S. courts have ordered.

"What I cannot do as president is submit the country to such extortion," Fernandez said.

Under the U.S. court orders, Argentina must hand over $907 million to the plaintiffs before June 30, or lose the ability to use the U.S. financial system to pay an equal amount to holders of other Argentine bonds.

That could mean defaulting on the vast majority of the country's performing debts, which are held by bondholders who agreed previously to provide debt relief that enabled Argentina to rebound from its economic crisis of 2001.

Fernandez said she has experts working on ways to avoid such a default and keep Argentina's promises to pay those bondholders. But, she added, her government will not make the court-ordered payments to NML Capital Ltd. and other investors she calls "vulture funds."

"It's our obligation to take responsibility for paying our creditors, but not to become the victims of extortion by speculators," Fernandez said.

The president said her government has repeatedly shown its willingness and ability to negotiate debt accords, and called on her countrymen to "remain tranquil" despite the Supreme Court loss. "It was known that this would happen," she said.

The markets had expected Fernandez to take a hard stance, which could be tough on the economy. Argentine stocks plunged as economists, analysts and opposition politicians practically begged her to comply.

The justices not only rejected Argentina's appeal without comment -- they also ruled 7-1 that bondholders could force Argentina to reveal where it owns property around the world. That could make it easier to collect on other debts that have gone unpaid since Argentina's economy collapsed.

Justice Antonin Scalia wrote that U.S. federal law offers no shield to Argentina's assets. Justice Ruth Bader Ginsburg worried that this could expose even its embassies and military ships to seizure if the government doesn't pay.

"This is the end of the line for Argentina in the judicial appeal process. It has nowhere else to turn," said Richard Samp, a lawyer for the Washington Legal Foundation who lobbies for plaintiffs that included NML Capital Ltd., the hedge fund owned by New York billionaire Paul Singer, told The Associated Press.

Argentina could win a delay of a few weeks by asking for a rehearing, but they are almost never granted.

Bowing to the U.S. courts would force Fernandez to betray a pillar of the government that she and her late husband and predecessor, Nestor Kirchner, have led since he won the presidency in 2003: That Argentina must maintain its sovereignty and economic independence at any cost.

Paying off the lawsuit winners in the way the courts have ordered also would encourage a long line of other creditors to seek similar treatment. Fernandez said Monday night those creditors together hold $15 billion in defaulted debt, or more than half the Central Bank's remaining foreign reserves, and that paying it all immediately in cash "is not only absurd but impossible."

In addition, Fernandez said, there's the near certainty "that the other 92 percent of bondholders will find a judge who will tell them that they, too, have the same rights," leading to "the more than certain possibility that the economy will crash."

Refusing to comply could win applause from her core supporters, because paying the plaintiffs 100 percent plus interest in cash would mean sacrificing the subsidies and populist programs that enabled her to win re-election by a landslide.

But while she and Singer jockey for any remaining advantage ahead of the inevitable negotiations over Argentina's debt payments, the immediate economic outlook could be grim.

Argentina's Merval stock index dropped 11 percent after the court decision, its largest one-day loss in more than six months. Share prices for the state-run YPF energy company fell nearly 13 percent, while the Edenor electricity utility plummeted 20 percent. The cost of insuring Argentine bonds against default soared, and the value of Argentina's currency plunged to 12 pesos to the dollar on the black market, implying a 33 percent loss to anyone needing to buy foreign currency legally.

Refusing to comply was "the best option" among a series of grim alternatives that Cleary, Gottlieb, U.S. law firm representing Argentina in Washington, presented to Fernandez ahead of the Supreme Court decision. Defaulting first could be Argentina's last hope for leverage in negotiations with the holdouts, the firm said.

The Associated Press contributed to this report.