The US Senate has cleared the way for a long debate on proposals to curb gun violence, rejecting an effort by conservative Republicans to block consideration of gun-control legislation prompted by December's Newtown school massacre.
The Senate voted 68-31 on Thursday to open debate on President Barack Obama's proposals to expand background checks for gun buyers, tighten restrictions on gun trafficking and increase funding for school security.
The Senate easily cleared the 60-vote hurdle needed to break a Republican filibuster on a bill that has sparked intense lobbying on both sides, including families of the Connecticut victims as well as the powerful gun lobby the National Rifle Association.
"The hard work starts now," Senate Majority Leader Harry Reid, a Democrat, said after the procedural vote to open debate, which won the support of 16 Republicans.
Al Jazeera's Kimberly Halkett, reporting from Washington DC, said while the senate vote was a "significant victory for gun-control advocates", 30 hours of debate still lay ahead.
"And it's not a continuous clock - which means it could be days, it could be weeks, likely, before we see a vote in the senate on the gun control bill.
"Now, at the same time, Republicans are vowing to continue to try draw this out as much as they can to try and rally support and get votes against this. So there still is a long way for this to go."
Twenty-nine Republicans and two Democrats voted to block the gun-control debate.
The Democrats were Mark Pryor of Arkansas and Mark Begich of Alaska, who face tough re-election campaigns next year in conservative, gun-friendly states.
The legislation still faces many hurdles, including a weeks-long debate in the Senate featuring many amendments that could make the bill unacceptable to senators who now support it.
And if it clears the Senate, it would face a tough reception in the Republican-led House of Representatives.
No major gun legislation has passed the US Congress since 1994.
The vote to proceed with the bill came a day after a compromise agreement on background checks between prominent defenders of gun rights from each party - Democrat Joe Manchin of West Virginia and Republican Patrick Toomey of Pennsylvania.
That agreement to expand criminal background checks of gun buyers to include commercial sales made at gun shows and online was expected to boost bipartisan Senate support for the measure.
Reid said the expanded background checks, a provision that polls show has the support of up to 90 percent of Americans, will be the first amendment offered in debate.
Some elements unlikely
Obama is unlikely to get some elements of gun control that he has advocated, including a ban on rapid-firing "assault" weapons like the one used in Connecticut and limits on the capacity of ammunition magazines.
Reid said amendments to add those provisions to the bill also would be considered by the Senate. Both amendments appear to have a slim chance of winning on the Senate floor.
Obama has called the Newtown tragedy- a shooting incident at a Connecticut school which left 20 children and six adults dead - the worst day of his presidency and has made passage of legislation to curb gun violence one of his top domestic policy priorities.
He has given recent speeches trying to build public support for gun control, including an appearance last week in Colorado, scene of two of the deadliest gun massacres in American history, and in Connecticut on Monday.
Some family members of Newtown victims flew to Washington DC from Connecticut on Obama's Air Force One jet to press senators to move forward on gun legislation.