Updated: 6:28 p.m.

As bipartisan criticism mounted Wednesday concerning U.S. military involvement in Libya, Speaker John Boehner called on President Barack Obama to respond to “fundamental questions about our engagement” in the region.

In a letter to Obama, the Ohio Republican said Members “are troubled that U.S. military resources were committed to war without clearly defining for the American people, the Congress, and our troops what the mission in Libya is and what America’s role is in achieving that mission.”

Boehner asked Obama to clarify whether Libyan leader Moammar Gaddafi must step down, as he has previously stated, and which foreign allies will take the lead in enforcing a no-fly zone over the North African country. The United Nations Security Council authorized the no-fly zone Thursday in response to the Libyan government’s violent crackdown on political opponents, but it did not include regime change as a goal of the mission.

An international coalition led by the U.S. military began enforcing the zone Saturday, but the Obama administration has said that it plans to quickly hand off primary responsibility and take a supporting role.

Boehner also called for a timeline for the mission and asked how much the effort would cost.

“The American people deserve answers to these questions. And all of these concerns point to a fundamental question: what is your benchmark for success in Libya?” Boehner wrote.

Rep. Dennis Kucinich (D-Ohio) has criticized Obama for not seeking a declaration of war from Congress and has characterized the president’s actions as an impeachable offense, while Republicans and Democrats alike have expressed discomfort at their lack of input.

Sen. Dick Lugar, the ranking member of the Foreign Relations Committee, requested Wednesday that the panel hold hearings on the intervention.

“Any U.S. military intervention in a foreign country would require oversight hearings by the Foreign Relations Committee,” the Indiana Republican wrote to Foreign Relations Chairman John Kerry (D-Mass.). “In my judgment, hearings on Libya are especially vital because the Obama Administration did not consult meaningfully with Congress before initiating military operations. … It is not clear that the Obama Administration has thought through the consequences of this action for regional stability, the fight against terrorism, the impact on oil markets, and other factors.”

Boehner echoed some of the concerns in his letter Wednesday.

“It is regrettable that no opportunity was afforded to consult with Congressional leaders, as was the custom of your predecessors, before your decision as Commander-in-Chief to deploy into combat the men and women of our Armed Forces,” he wrote.

White House Press Secretary Jay Carney accused critics of previously faulting the administration for not intervening sooner in Libya.

“We obviously take very seriously the need for Congressional consultations,” Carney told pool reporters Wednesday on the flight back to the United States from El Salvador, where Obama had wrapped up a five-day tour of three Latin American nations. “We have done them and will continue to do them. I would also say that it’s important to remember that in the runup to this action we were criticized somewhat, in fact fairly frequently, by those who felt like we weren’t moving quickly enough. And now there are some who are criticizing us for not going — for going too quickly. What the president did was make an action based on … an imminent threat of a humanitarian nature to a great number of Libyans, and he has done that with a great number of consultations with Congress that will continue.” 

House Minority Leader Nancy Pelosi was careful in a statement Wednesday to show her support for military intervention, while urging the president to bring Congress into the discussion.

“The United States joined the international community in preventing an imminent humanitarian crisis in Libya. … Decisions made in the days ahead are strengthened by our NATO partners’ participation,” the California Democrat said. “U.S. participation is strengthened by the President’s continued consultation with Congress.”

Three top Senate Democrats came to Obama’s defense Wednesday, praising his handling of the situation during a conference call with reporters.

“The reports are positive” about the intervention, Senate Majority Whip Dick Durbin said. The Illinois Democrat was joined on the call with Armed Services Chairman Carl Levin (Mich.) and Armed Services member Jack Reed (R.I.).