The Navy will keep four destroyers in the eastern Mediterranean and an aircraft carrier strike group in the Red Sea to maintain a “strong military posture” for a potential strike on Syria, the Pentagon said Thursday.

“We have no plans at this time to change our military posture in the Mediterranean,” Pentagon press secretary George Little said. “We’re prepared for any potential military contingencies that might involve Syria.”

U.S. officials have voiced the need for continuing to apply military pressure on Syria as the Obama administration explores a possible diplomatic solution by working with Russia through the United Nations to dismantle Syria’s chemical weapons program.

“There are potential diplomatic scenarios that could lead to positive developments, so we’re clear-eyed about those discussions with the Russians, and we need to see where they go. But we believe very strongly that the credible threat of military strikes has enabled the diplomatic process to unfold,” Mr. Little said.

The USS Nimitz carrier strike group, which has two destroyers and a guided-missile cruiser, has been extended for an additional two weeks in the Red Sea from the date it was due to start returning home to the Pacific Coast.

The destroyer USS Stout recently entered the Mediterranean to replace the USS Barry, the deployment of which in the region has been extended. Two other destroyers — the USS Ramage and the USS Gravely — also are deployed in the Mediterranean.

Navy officials said it would cost at least $2 million per week to keep a destroyer extended beyond a scheduled deployment and between $25 to $40 million per week to extend a carrier strike group, depending on the tempo of operations.

If costs continue beyond the start of the fiscal year on Oct. 1, the Navy will have to take actions to absorb extra costs, such as requesting supplemental funding from Congress, borrowing from the last quarter of the fiscal 2014 budget or taking funds from another program.

The Pentagon pushed back against the idea that costs would affect any operations regarding Syria.

“If this country decides it is in our national interest to conduct a military option, then this country has historically found a way to fund it,” Mr. Little said.

Defense Secretary Chuck Hagel on Thursday hosted a bipartisan breakfast meeting with five members of Congress to discuss Syria.

“I don’t think it was arm-twisting. I think it was an honest, open, candid discussion,” Mr. Little said of the meeting. “Ongoing engagement is the name of the game.”

“The option that we’ve been contemplating is limited in duration and scope, and it will involve no boots on the ground,” he said. “It is in the national interest of the United States to ensure that chemical weapons are not used. We’re going to maintain a strong military posture.”