Top U.S. congressional leaders from the Democratic Party came close to finalizing major U.S. health care legislation Friday, while President Obama pushed for quick action prior to a special Senate election that threatens to derail his biggest domestic policy initiative.

Congressional negotiators reported progress after meeting for a third straight day, and said they aimed to send the bill's major provisions to the non-partisan Congressional Budget Office in the coming days for cost estimates.

The talks have gained urgency with opinion polls indicating the Democratic candidate, Martha Coakley, could lose next week's special Massachusetts election to replace the late Senator Edward Kennedy.

A victory by the Republican, Scott Brown, would cost the Democrats their 60th Senate seat, stripping them of their supermajority and eliminating their power to override Republican delaying tactics on contentious legislation, particularly heath care reform.

President Obama will travel to Massachusetts Sunday to campaign for Coakley.

Democratic sources said Thursday they reached a tentative deal on how to pay for the health care overhaul, including a tax on high-price, employer-provided health plans.  The Senate included the tax in its version, but the House opposed the fee, saying it would hurt middle-class families.

Democrats hope to finalize health care reform before Mr. Obama delivers his annual State of the Union address to Congress, which is expected by early February.

Despite a few remaining differences, the two bills are in accord on expanding coverage to more than 90 percent of Americans under the age of 65.  The two bills also seek to stop alleged abusive practices by private health insurers, and to lower the rising cost of health care for families and small businesses.

Some information for this report was provided by AP, AFP and Reuters.