WASHINGTON (AP) — The House on Thursday weighed whether to prohibit funds for the U.S. military operation against Libya in a constitutional showdown with President Barack Obama.

Calling the war illegal because Obama never sought congressional consent, Republicans and Democrats pressed for two measures — one to bar funds for military activities and equipment used against Libya, and a second to prevent funds for U.S. military participation in the NATO-led mission against Moammar Gadhafi’s forces.

Lawmakers argue that Obama violated the 1973 War Powers Resolution that requires a president to seek congressional approval within 60 days of the first military strikes, a move the commander in chief did not make. Instead, Obama informed Congress last month that such assent was unnecessary because the limited U.S. role does not rise to full-blown hostilities.

Incensed House Republicans and Democrats voted overwhelmingly last month to deny Obama the authority to continue the mission, a largely symbolic vote that was still a rebuke to the president.

The move Thursday to cut off funds ratcheted up the pressure on the administration as Libya remained a stalemate between Gadhafi and rebel forces, and war-weary NATO allies signaled their patience was wearing thin. Italy announced that it was reducing its participation in NATO’s campaign by removing an aircraft carrier from the region and pulling thousands of troops home.

Calling the conflict “illegal and unauthorized,” Rep. Tom Cole, R-Okla., sponsor of the first measure, said Libya “did not attack us, did not attack NATO … quite simply, however much we detest Mr. Gadhafi and his regime, we have no reason to be at war.”

Rep. Justin Amash, R-Mich., a co-sponsor of the second measure, said the House had an “opportunity to stop this unconstitutional war against Libya.”

The House considered the measures as part of a $649 billion defense spending bill that wouldn’t go into effect until Oct. 1. The defense bill includes no funds for the Libyan operation — the Pentagon has said it could cover the expense with existing funds — but the measures would effectively bar funds for the mission.

Last month, the White House put the cost of U.S. military operations in Libya at about $715 million, with the total increasing to $1.1 billion by early September.

Since NATO took command of the Libya operation in early April, the U.S. role has largely been limited to support efforts such as intelligence, surveillance and electronic warfare. The U.S. has launched airstrikes and drone attacks, flying more than 3,400 sorties.

Copyright 2011 The Associated Press.