Members of Congress generally expressed support Tuesday for the White House’s plan to respond to violence related to the illegal drug trade on the U.S.-Mexico border, but lawmakers already had questions about the initiative.

The Obama administration announced the plan Tuesday morning, on the eve of Secretary of State Hillary Rodham Clinton ’s trip to Mexico to meet with President Felipe Calderón. Two White House entities — the National Security Council and the Homeland Security Council — will coordinate the initiative, which also will involve the departments of Defense, Homeland Security, Justice, State and Treasury.

Lawmakers said they want more details about the plan and what the congressional role will be.

Joseph I. Lieberman , I-Conn., chairman of the Senate Homeland Security and Governmental Affairs Committee, said he strongly supports the initiative but intends to ask for more information from Homeland Security Secretary Janet Napolitano and witnesses from the State and Justice departments when they appear Wednesday before his committee.

“For example, I would like to know how the administration plans to increase coordination between federal state and local officials along the border; how the State Department plans to expedite the expenditure of money appropriated through the Merida initiative; and whether the Justice Department needs additional authority to track laundered drug money or crack down on the illegal purchase and exportation of high-caliber firearms,” Lieberman said.

Rep. Lamar Smith of Texas, ranking Republican on the Judiciary Committee, said he supports efforts to address violence on the border but has concerns about the specifics of the plan.

“I am concerned that the redeployment may come at the expense of other critical law enforcement activities,” Smith said. “The administration appears to be using border violence as an excuse to reduce interior enforcement of our immigration laws and enact gun restrictions.”

Peter T. King of New York, the top Republican on the House Homeland Security Committee, echoed that sentiment.

“I support Secretary Napolitano’s decision to deploy additional personnel to the border. I would hope this will not in any way lessen interior enforcement,” King said. “Should Secretary Napolitano need more border personnel, I would certainly support that request.”

Bennie Thompson , D-Miss., chairman of the House Homeland panel, applauded “the administration’s decisive action” saying it “exemplifies the importance of coordination and cooperation with state and locals and our partners in Mexico.”

Napolitano said the situation on the border “requires immediate action.”

“We are guided by two very clear objectives. First, we are going to do everything we can to prevent the violence in Mexico from spilling over across the border,” she said. “And second, we will do all in our power to help President Calderón crack down on these drug cartels in Mexico.”

The White House said the effort will include $700 million to help Mexican law enforcement and judicial systems to battle drug cartels under the Merida Initiative, a partnership involving the United States, Mexico and several nations in Central America and the Caribbean. The program aims to provide training, equipment and intelligence to fight drug trafficking, transnational crime and money laundering.