The Republican Party on Monday stepped up its fight against any U.S. Supreme Court nominee put forward by President Barack Obama while the president's allies hit back against a conservative group's attack on a judge who had been considered for the job.

The Republican Party's move to create a task force to coordinate advertising and other steps to assail Obama's nominee to fill the vacancy left by the Feb. 13 death of conservative Justice Antonin Scalia is the latest indication that the political fight could become very nasty.

"It's clear what Republicans are planning to do," White House spokesman Josh Earnest said. "They are planning to tear down the president's nominee, without regard to who that person is."