South Korea's rival political parties showed mixed reactions Friday after Seoul and Washington agreed to delay the transfer of wartime troop control to Seoul with no new date set.

On Thursday, the allies agreed to postpone the transfer of wartime operational control (OPCON) until Seoul improves capabilities to counter nuclear and missile threats from North Korea.

The transfer was scheduled for late 2015 after being postponed four years earlier. Officials from both sides said the new target year could be around the mid-2020s.

South Korea currently has peacetime control of its approximately 639,000 service members, but control in the case of war transfers to a U.S. four-star general under the Combined Forces Command.

South Korea's ruling Saenuri Party said the delay was necessary given the current security situation on the Korean Peninsula.

"For the OPCON transfer, our security environment and other conditions are more important than timing," Rep. Won Yoo-chul of the ruling party said. "It was appropriate to delay the OPCON transfer again under such conditions."

Rep. Shim Yoon-joe of the same party said the allies made the "right decision" amid North Korea's growing nuclear and missile capabilities and mounting military threats against the South.

The main opposition New Politics Alliance for Democracy (NPAD), however, criticized the move as lacking basis.

"It is truly worrying that the people's wishes to correct this abnormal situation in which wartime command over our troops is given to another country have been neglected in this way," Rep.

Moon Hee-sang, NPAD's interim leader, said during a party meeting.

Rep. Sim Jae-kwon of the opposition party claimed the three conditions for OPCON transfer are "too comprehensive and vague" and suggest there will be no transfer until after the reunification of the two Koreas.

Under Thursday's agreement, the handover will take place when the overall security situation can guarantee a stable transition, when South Korea is equipped with core military capabilities to lead the combined defense posture, and when it is able to effectively guard against North Korea's nuclear and missiles attacks in the early stages of local provocations and full-scale wars.

Rep. Kim Sung-gon of NPAD called the conditions "abstract,"

saying he doubts whether Washington's retention of OPCON will help ease tensions on the Korean Peninsula and bring peace to Northeast Asia.

Some opposition lawmakers called on President Park Geun-hye to apologize for the delay, which they claimed was caused by a failure in the national security policies of her conservative administration and that of her predecessor Lee Myung-bak.

"As commander-in-chief of our armed forces, President Park should apologize to the people for this tragic reality in which we ourselves have given up our military sovereignty," Rep. Chung Sye-kyun of NPAD said.

Park's office declined to comment on the opposition's accusations that Park broke her election pledge to prepare for the scheduled OPCON transfer in 2015.

The delay was anticipated under the current security conditions while Park and other government officials kept the public well-informed of recent developments that made it difficult to keep the pledge, presidential officials said.

The opposition party also leveled criticism at National Security Adviser Kim Kwan-jin, citing his involvement in the signing of an agreement to retake wartime OPCON as then chairman of the Joint Chiefs of Staff during the 2003-2008 liberal administration of then President Roh Moo-hyun.

"(Kim) displayed a soulless attitude," Rep. Jin Sung-joon of NPAD told Yonhap by phone. "He denied himself before the great will of the president." (Yonhap)