WASHINGTON — Attempts to pass a sweeping overhaul of financial regulations stalled in the Senate Wednesday as a key procedural vote failed because of near-unanimous Republican opposition and concerns from two Democrats the legislation was not tough enough on Wall Street.

Senate Democratic leaders failed to get the 60 votes needed to end debate on the legislation and bring the sweeping financial reform legislation to a final vote.

The failure caused partisan tensions to flare. But another vote was scheduled for today and key Democrats said they were hopeful they could overcome the procedural hurdle.

“We’re going to keep this fight going. We’ve got to win this fight,” said Sen. Dick Durbin, D-Ill. “The American people are counting on us to make these changes, to guarantee we don’t face another recession like this again.”

Senate Democratic leaders fell two votes short of ending debate, though the final tally was 57-42. In another indication of optimism they would eventually prevail, Majority Leader Harry Reid of Nevada changed his vote to “no” to make it easier to hold another vote.

Democrats noted it took three similar attempts last month to overcome strong Republican opposition and gain the 60 votes necessary to start work on the legislation. Most Republicans continue to oppose the legislation as an unnecessary expansion of government regulation.

But two Republicans, Sens. Susan Collins and Olympia Snowe of Maine, broke ranks Wednesday and joined with Democrats in voting to end debate.

The legislation is a top priority of the Obama administration and congressional Democratic leaders.

It would create an independent bureau in the Federal Reserve to protect consumers in the financial marketplace, grant the government power to seize and dismantle teetering firms whose failure would pose a danger to the economy, impanel a council of regulators to monitor the financial system for major risks and impose strict regulations on complex financial derivatives.

Democrats could be helped by the potential return to Washington of Sen. Arlen Specter, D-Pa., who missed Wednesday’s vote after losing his re-election primary. His office did not respond to calls about whether he would be back today.