WASHINGTON -- The United States is committed to the envisioned transition of the wartime operational control (OPCON) of South Korean forces back to Seoul, but it will take time to meet the required conditions, US Defense Secretary Mark Esper said Wednesday.

Esper made the remark at the start of annual defense talks with his South Korean counterpart, Suh Wook, amid growing speculation that the OPCON transfer is unlikely to be completed before the term of President Moon Jae-in ends in May 2022.

"Fully meeting all the conditions for the transition of operational control to a ROK commander will take time, but the process of doing so will strengthen our alliance," Esper said at the start of the Security Consultative Meeting (SCM).

In a joint communique, however, the two sides noted that "great progress" has been made.

"The Secretary and the Minister acknowledged that great progress had been made toward meeting the conditions for wartime OPCON transition through US-ROK joint efforts," said a joint communique released after the SCM. ROK stands for South Korea's official name, the Republic of Korea.

Esper and Suh had been scheduled to hold a joint news conference after the talks, but the US called it off at the last minute, officials said. That raised speculation that it could be because of wide differences between the two sides on pending issues like the OPCON transfer.

South Korea is seeking to retake the wartime OPCON before Moon leaves office. The country retook its peacetime OPCON in 1994.

Under the so-called Conditions-based OPCON Transition Plans, signed in 2015 and 2018, Seoul and Washington first need to identify and reinforce South Korea's command capabilities to control its troops in the event of a war.

Their efforts, however, have been delayed partly due to the COVID-19 pandemic but also because of the cancellation or reduction of their joint military exercises, a concession made by US President Donald Trump to North Korea.

Esper reaffirmed his country's commitment to providing the necessary supplements to Seoul's command capabilities but said they will first have to identify what capabilities Seoul requires.

"The Secretary committed to the provision of bridging capabilities but noted the need first to understand ROK acquisition plans in order to determine what specific capabilities are needed, and for how long," the joint communique said.

Suh said his country will continue to acquire all necessary capabilities.

"The Minister noted that the ROK will acquire, develop, and provide these capabilities, and committed to more robust discussions on ROK acquisition planning," the released statement said.

South Korea and the United States mark the 70th anniversary of signing their bilateral military alliance this year. Wednesday's SCM marked the 52nd of its kind.

"The Secretary and the Minister assessed that the US-ROK Alliance is strong and reaffirmed the two nations' mutual commitment to a combined defense as agreed in the US-ROK Mutual Defense Treaty to defend the ROK," the joint statement said.

"Both sides pledged to continue to develop the Alliance -- the linchpin of peace and stability on the Korean Peninsula and in Northeast Asia -- in a mutually reinforcing and future-oriented manner," it added.

Suh and Esper agreed on the need to quickly conclude the countries' stalled negotiations to set South Korea's share in the cost of maintaining some 28,500 US troops on the peninsula.

"The Secretary offered his appreciation for the ROK's contributions toward ensuring a stable stationing environment for US forces in Korea while emphasizing the importance of defense cost-sharing," the statement said.

Seoul and Washington have held several rounds of negotiations for the so-called Special Measures Agreement (SMA) since late last year, but the talks currently remain deadlocked.

South Korea has offered to increase its annual share by up to 13 percent from the $870 million paid under last year's agreement, but the US is said to be demanding a 50 percent hike to $1.3 billion while US President Donald Trump is reported to have initially demanded $5 billion per year from Seoul.

Trump is also said to have instructed US negotiators to use a possible withdrawal of US forces in Korea as a bargaining chip.

The US defense secretary earlier called for a more "equitable" agreement.

"I know we will have an open and candid discussion on this front. And I hope we will all agree on the necessity of reaching a Special Measures Agreement as soon as possible to ensure the stable stationing of US forces on the Korean peninsula," Esper said at the start of Wednesday's meeting.

"The two sides concurred in the necessity of expeditiously resolving the SMA negotiations, in a fair, equitable, and mutually agreeable manner, particularly in light of the impact of the lapse on the ROK-US Alliance," the released statement said.

Unlike past statements, however, the joint communique from the latest SCM did not mention the US' commitment to maintaining its troop levels in South Korea.

A South Korean official later explained it did not mean a possible reduction.

"It does not mean anything significant," the official told reporters, noting the defense chiefs instead reaffirmed their commitment to maintaining the alliance's joint defense readiness as seen in their joint communique.

The two defense chiefs also reaffirmed their joint efforts to denuclearize North Korea, noting the communist state's nuclear and ballistic missile programs continue to pose serious threats to international security.

"In recognition of the significant threat that North Korea's nuclear and ballistic missile programs pose to international security, both sides reaffirmed the need for close coordination and cooperation to establish a permanent peace on the Korean Peninsula through complete denuclearization of the Democratic People's Republic of Korea (DPRK), as well as dismantlement of its ballistic missile program," said the statement, referring to North Korea by its official name.

The call came days after the communist state unveiled a new intercontinental ballistic missile at a military parade over the weekend that many believe may reach most of US mainland.

Trump and Kim have held two more meetings since their Singapore summit in June 2018, but their talks have stalled since their second summit, held in Hanoi in February 2019, ended without a deal.

Suh and Esper underlined the importance of the countries' joint military exercises to ensure their defense readiness.

"The Secretary and the Minister reaffirmed the need to continue to conduct combined exercises and training events on the Peninsula to strengthen Alliance readiness," said the statement.

"The two leaders also emphasized that continuous training opportunities for USFK are critical to maintaining a strong combined defense posture," it added. (Yonhap)