WASHINGTON (AP) — Secretary of State Rex Tillerson declared Tuesday he is "offended" by the growing number of critical reports of his leadership, which accuse him of dismantling the State Department for political reasons.

In a speech to a Washington think tank, Tillerson defended his support of a White House proposal to slash nearly 30 percent of the agency's budget and cut its workforce by 8 percent. He repeated an argument he made to skeptical lawmakers that the budget is "unsustainable" at its previous level of nearly $55 billion. He didn't elaborate further.

Tillerson pointedly denied the claims he is "hollowing out" the diplomatic ranks by forcing out senior officials, pushing early retirements and delaying promotions to encourage departures.

Speaking at the Wilson Center, he said such complaints are offensive to the men and women who work at the department.

"I am offended on their behalf that somehow we don't have a State Department that works," said Tillerson, who has been engaged for several months in an effort to redesign the 70,000-person strong agency.

He spoke shortly after The New York Times published the latest broadside from two of the department's most respected retired career diplomats — former ambassadors Ryan Crocker and Nick Burns. They accused Tillerson of destroying the U.S. Foreign Service.

"This is not about belt tightening," they wrote. "It is a deliberate effort to deconstruct the State Department and the Foreign Service."

Tillerson fired back.

"These numbers that people are throwing out are just wrong," the former Exxon Mobil CEO said, pointing to one widely reported figure that 60 percent of the department's "career ambassadors" had retired or resigned since the beginning of the year.

While that percentage is correct, Tillerson said it is highly misleading. Only five officials held that rank when he came into office. Two remain.

He pointed to employment statistics the department provided to Congress earlier this month that show only slight declines in the numbers of other senior-ranking diplomats and stressed that retirements this year are on roughly the same pace in 2016. He said that the total number of foreign service officers is now only about 10 fewer than it was last year.

"We are keeping the organization fully staffed," Tillerson said. "There is no hollowing out."