Srinivasan or Garland likely Obama choice for U.S. Supreme Court: source

President Barack Obama is likely to announce either Judge Sri Srinivasan or Judge Merrick Garland as his pick for U.S. Supreme Court nominee and the announcement could come as early as Wednesday, a source familiar with the selection process said.

The team of advisers helping to vet candidates, line up their public supporters and answer the president's questions had finished its work, the source said on Tuesday.

Obama is searching for a replacement for long-serving conservative Justice Antonin Scalia, who died on Feb. 13. With Scalia's death, the court is divided 4-4 between conservatives and liberals. Obama's nominee could move the court to the left for the first time in decades.

Republicans, who control the U.S. Senate, have vowed not to hold confirmation hearings or an up-or-down vote on any nominee picked by the Democratic president for the lifetime position on the court. Senate confirmation is required for any nominee to join the bench.

Senate Majority Leader Mitch McConnell has suggested there might be no point even in holding the traditional "courtesy call" meetings with whomever Obama nominates, infuriating Senate Minority Leader Harry Reid and his fellow Democrats.

Republicans, hoping a candidate from their party wins the Nov. 8 presidential election, want the next president, who takes office in January, to make the selection. Billionaire Donald Trump is the leading Republican presidential candidate; Obama's former secretary of state, Hillary Clinton, is the front-runner on the Democratic side.

Without Scalia, the Supreme Court is evenly split with four liberals and four conservatives. An Obama appointment could tilt the court to the left for the first time in decades.

Both Srinivasan and Garland are seen as having unique attributes that could weigh heavily in Obama's decision.