WASHINGTON (Reuters) - Two senior U.S. senators asked Secretary of State Rex Tillerson on Wednesday to explain “questionable management practices” at his department that they believe are weakening the country’s diplomatic power, adding to a chorus of concern in Congress.

U.S. Secretary of State Rex Tillerson attends as U.S. President Donald Trump holds a bilateral meeting with India's Prime Minister Narendra Modi alongside the ASEAN Summit in Manila, Philippines November 13, 2017. REUTERS/Jonathan Ernst

Republican Senator John McCain and Democratic Senator Jeanne Shaheen delivered a letter to Tillerson asking him to begin consulting with lawmakers on decisions that have an impact on recruiting, retaining and staffing the State Department, removing a hiring freeze and resuming promotions.

McCain is chairman of the Senate Armed Services Committee and Shaheen is the top Democrat on the Senate Foreign Relations Committee’s subcommittee on State Department management.

“While we support reasonable steps to improve the efficiency of the State Department, such efforts must be fully transparent, with the objective of enhancing, not diminishing, American diplomacy,” the senators wrote.

They said declining morale, recruitment and retention of staff, a lack of experienced leadership and reports that diplomacy is becoming less effective “paint a disturbing picture.”

Many members of Congress, Democrats as well as some of President Donald Trump’s fellow Republicans, have rejected Trump’s proposal to cut the State Department budget by about 30 percent. Tillerson has embraced the plan, and imposed a hiring freeze while analyzing the agency’s operations and deciding how to reorganize them.

On Tuesday, the Republican chairman and top Democrat on the Senate Foreign Relations Committee both blasted the agency for cuts in staff and what they described as a failure to have a plan for a proposed organization.

The panel’s top Democrat, Senator Ben Cardin, reiterated his concerns on Wednesday.

“Our national security is being jeopardized by the employment and career decisions being made at the State Department,” he told reporters.

It was not immediately clear how lawmakers could press the administration to change its policies, especially because Trump’s fellow Republicans, most of whom vote consistently with the president, hold majorities in both the Senate and the House of Representatives.

A State Department representative said the department had received the letter and would “appropriately respond.”

Tillerson has said his reorganization plan aimed to increase efficiency and to cut costs, with a target of saving at least 10 percent, or about $5 billion, over the next five years from fiscal-year 2017 levels.

Cardin said the impact of disorganization at the State Department was being felt internationally.

“I could mention almost every place in the world,” he said.