President Donald Trump speaks during a meeting with Irish Prime Minister Leo Varadkar in the Oval Office of the White House, Thursday, March 12, 2020, in Washington.

WASHINGTON (AP) — President Donald Trump is preparing to invoke emergency powers over the coronavirus outbreak, an emerging development Friday as an aid package teetered in Congress without his full public support.

The president's decision to move ahead was confirmed by two people familiar with the planning who spoke on condition of anonymity. It was still unclear, however, what mechanism Trump would use to free up additional federal resources for testing and treatment as well as for helping those struggling with the economic fallout.

Trump is poised to speak at 3 p.m. at the White House. "Topic: CoronaVirus!" he tweeted.

The abrupt move comes as House Speaker Nancy Pelosi and the Trump administration are laboring to finish the coronavirus aid package. Central to that effort is free testing for the virus and guaranteed sick pay for workers who are taking time away from jobs, along with an infusion of dollars to handle unemployment benefits and boost food programs for children, families and seniors.