(Adds further details, background.)
WASHINGTON, Sept 4 (Reuters) - U.S. President Barack Obama's administration is dispatching senior intelligence officials to provide an in-depth briefing on the Islamic State militant group to key members of Congress and staff, a congressional aide said on Thursday.
The briefing from the Office of the Director of National Intelligence and National Counterterrorism Center will take place on Friday, the aide said.
Participants from Congress will include leadership and staff of the House of Representatives Intelligence Committee, Foreign Affairs Committee, Armed Services Committee and defense and foreign operations appropriations subcommittees will take place on Friday, the aide told Reuters.
He said additional officials would likely join the session, which was intended to provide more detailed information to lawmakers than previously available to them.
Obama has formally informed Congress that he had authorized air strikes and humanitarian airdrops in Iraq to counter the threat from Sunni militant fighters, as he is required to do under the War Powers Act.
However, the act gives presidents authority for only temporary military action, and Obama would have to seek Congress' approval for action lasting more than 60 days.
Several lawmakers - both Republicans and Obama's fellow Democrats - have complained that the administration has failed to consult them sufficiently or present a strategy for dealing with the Islamic State.
Obama said on Wednesday that the United States plans to fight Islamic State until it is no longer a force in the Middle East. (Reporting by Patricia Zengerle; Editing by Doina Chiacu)