WASHINGTON — Defense Secretary William Cohen wants to close more military bases because the $14 billion savings from four rounds of shutdowns since 1988 are not enough, the Pentagon said Tuesday.

Cohen wants Congress to approve two separate sets of closures in 1999 and 2001 on top of the nearly 100 sites ordered shut down in recent years, Pentagon sources said. But harsh reactions from key lawmakers indicated Cohen won’t win approval without a fight.

“Closing bases is never easy. … It’s time-consuming, it’s emotional … but it worked,” Pentagon spokesman Kenneth Bacon said after disclosing Cohen’s decision at a briefing.

Bacon declined to say exactly how many closings Cohen was seeking or what sites might be targeted. But military maintenance depots would be considered for closures along with bases, he said.

In response to the briefing, U.S. Sen. Olympia Snowe said, “Although I have seen Secretary Cohen’s comments about base closing, there has been no annoucement of congressional notification that the Department of Defense has yet decided to conduct another round of base closings. Any such process would require approval from Congress.”

Snowe said she opposed the Base Closure and Realignment Commission process from its beginning, and would “oppose any attempt to resurrect it in the future.”

Sen. Susan Collins said she, too, was stongly opposed to another round of base closures “because of our disastrous experience in the last round, when Loring Air Force Base was shut down for specious quality of life reasons. I have no confidence in the former base closure process and will resist its resurrection as forcefully as I can.”

U.S. Rep. Tom Allen said he is looking forward to receiving more information about the possible base closings. “But I am prepared to fight any proposal to close either the Portsmouth Naval Shipyard or the Brunswick Naval Air Station. Both bases play a vital role in the nation’s defense.”

Congress approved legislation that began four rounds of base closures in 1988, shutting down 97 sites.

Once those closures are completed in 2001, some $14 billion in net savings will have been achieved, Bacon said. Closing some bases has been more costly than expected because of environmental cleanup and legal costs, he added.

Bacon said he could not answer how much money Cohen wants to save through additional closures.

Rep. Ike Skelton, D-Mo., said in a statement issued to reporters that he doubts Congress will approve additional base cuts.

“We have not … been able to reduce the size of the defense infrastructure in proportion to the size of the force, said Skelton, a member of the House National Security Committee. “I am very doubtful Congress will approve another round of base closures in the near future.”

“Does `Over my dead body!’ make it clear enough?” Rep. Joel Hefley, R-Colo., chairman of the House National Security subcommittee on military installations, said Tuesday when asked about potential closures.

Cohen has pointed out repeatedly that post-Cold War reductions in the military have pared active duty forces by 33 percent but the military’s base structure by only 18 percent.

Bacon said the new secretary believes the law that established BRAC worked well and could work again.

Cohen, who is wrapping up a wide-ranging review of military strategy and resources, needs to find savings to help the military update its weaponry for the coming century. The accounts that had paid for such weapons were tapped repeatedly in past years to keep the military in fighting shape.

Military leaders need $15 billion annually over the next four years to pay for such weapons. Meanwhile, the administration is planning on holding Pentagon budgets annually to about $250 billion, putting pressure on Cohen to seek savings wherever he can.

“Congress will have to go through the same choices that the military faced,” and decide whether to pay for unneeded bases “or weapons to make our troops more effective in battle,” Bacon said.

Cohen’s review also is expected to propose slicing the 1.4-million active duty force by 60,000 men and women and cutting hundreds of warplanes from planned purchases of high-tech aircraft by the Air Force and Navy, say senior officials.

The Air Force wants 438 F-22 stealth fighters, but the proposal calls for only 339. The Navy has sought 1,000 of the newly improved F-A-18 Super Hornets, but the plan calls for 785, said a senior military officer.