The ruling People Power Party on Saturday called for efforts by the opposition-controlled National Assembly to swiftly ratify a new defense cost-sharing deal between South Korea and the United States.

Seoul and Washington inked the five-year deal, named the Special Measures Agreement, on Wednesday, about a month before the US presidential election to be held Nov. 5.

Under the agreement, South Korea will pay 1.52 trillion won ($1.14 billion) in 2026, up 8.3 percent from the previous year, for the upkeep of the 28,500-strong US Forces Korea.

The PPP said uncertainty surrounding the defense cost deal has decreased as the countries concluded their negotiations in a swift manner ahead of the US election.

"We expect that the conclusion of the deal will help strengthen a combined defense posture between South Korea and the US, and serve as an important occasion to bolster the alliance by consolidating mutual trust and bilateral cooperation," PPP spokesperson Kim Hye-ran said.

Kim stressed that the deal should be "consistently" honored regardless of the political situation, amid lingering uncertainty over whether the agreement can survive should former US President Donald Trump return to the White House.

"All diplomatic and legislative processes should be promptly pushed for to ensure that the deal can be smoothly implemented through the National Assembly's ratification," she said.

The deal came amid speculation that South Korea was seeking an early deal to apparently avoid tough negotiations in case Trump returns to office. Under Trump's presidency, the U.S. had demanded more than a fivefold hike in Seoul's payment to $5 billion.