Gov. George W. Bush's plans to claim victory this weekend were put on hold yesterday, after the Florida Supreme Court unexpectedly barred the state from certifying the results of the presidential election.

Bush's slim margin over Vice President Al Gore in Florida grew to 760 votes early this morning as overseas absentee ballots were counted, according to an unofficial Associated Press tally. Bush, the Republican candidate, was leading Democrat Gore by 1,057 to 597 in absentee ballots, based on returns from 65 of 67 counties.

But no winner will be declared in the Sunshine State until next week, at the earliest.

The court's decision to block Florida Secretary of State Katherine Harris from certifying Bush the winner this afternoon took both sides by surprise. Gore campaign lawyers had decided not to make a legal effort to stop her, explaining that her actions could be reversed later in the courts.

By allowing the hand counts to continue, at least until it has a chance to hear arguments in the case Monday afternoon, the state's high court has given Gore and the Democrats a chance to take an unofficial lead in a vote count that has, up to now, narrowly favored Bush.

The decision by the Democratic-dominated Florida court spared Gore, at least temporarily, from a serious public relations setback. Bush had been expected to use the certification by Harris to promote himself as the winner in Florida - and, presumably, as president-elect.

Gore, who was moments away from issuing a televised statement pleading with the nation for more time, praised the state Supreme Court ruling as "so important" to obtaining "a fair and accurate count to resolve this election."

Bush made no comment, and his campaign took more than three hours to react to the news. Former Secretary of State James A. Baker III read a terse statement expressing confidence that the court would eventually conclude that Harris "properly exercised her discretion and followed the law" in rejecting manual recounts.

A fourth county, Miami-Dade, the state's most populous, reversed a previous decision against manual tallies and announced yesterday that it would begin counting by hand.

Baker, the top Bush surrogate in Florida, pointed out that neither side had sought the state court's order barring Harris from certifying the election.

A top Republican in Congress was much less restrained. Rep. Tom DeLay of Texas, the Republican whip, said the court's order "reeks of judicial activism."

DeLay, who has circulated information to House members explaining how Congress has the power to reject the results of the Electoral College vote, accused the Florida court and the Gore campaign of "creating a situation that may result in a constitutional crisis. ... Make no mistake, we are witnessing nothing less than a theft in progress" of the election.

For the candidates, and their supporters, the 10th day of the grueling ballot-counting battle was perhaps the most turbulent.

By midmorning, Bush had appeared to take a major step toward winning the election when a Florida circuit judge cleared the way for Harris to certify Bush as the winner today. As local officials around the state began counting absentee ballots from overseas, Bush's lead began to grow, as Republicans figured it would, and Republicans appeared confident their candidate would prevail at last.

But, by nightfall, Gore had received his 11th-hour reprieve from Florida's highest court, and Democrats were expressing relief, based on early returns, that Bush's advantage in the overseas voting would be smaller than expected.

Meantime, Bush was dealt a second legal blow. A federal appeals court in Atlanta last night rejected his request to immediately stop the Florida hand counts. The Florida Supreme Court order delaying certification of the election results also allows the hand recounts to continue.

The rulings gave election officials more time to conduct the manual recounts, which appear to give Gore his only hope of winning Florida and the White House.

It is not clear whether Gore will pick up enough additional votes in the hand counts to overtake Bush. The vice president has been slowly gaining votes in the recounts, which could take up to a week or more to complete, county officials said.

Gore also needs a ruling from the Florida Supreme Court that the manual recounts must be included in the official tally by the state. Otherwise, he will lose.