The South Korean military has formally asked the Pentagon to provide detailed information on Terminal High Altitude Area Defense (THAAD) systems, an informed source here privy to defense issues said Thursday.

As part of efforts to bolster its missile defense against North Korea's threats, South Korea is apparently seeking to combine U.S.

technologies with its own, added the source.

"South Korea recently requested additional information on THAAD as well as PAC-III from the Pentagon, including prices and capabilities of the systems," the source told Yonhap News Agency.

The source said the missile defense issue was among major topics in the annual high-level military talks between the allies held in Seoul this month.

It's an open secret that the U.S. hopes for integrated missile defense systems with Japan and South Korea to enhance effectiveness and reduce costs.

U.S. defense officials have emphasized the need for South Korea to beef up its missile defense as Seoul seeks to delay the transfer of operational control (OPCON) from the U.S., slated for 2015. The OPCON transition would make South Korea play a leading role in its national defense, with U.S. Forces Korea shifting to support missions.

Speaking at the National Assembly earlier this week, South Korean Defense Minister Kim Kwan-jin said his military is pursuing "multi-layered" missile defense.

South Korea is in the process of upgrading its current PAC-II units to PAC-III.

Kim's remarks sparked media speculation that Seoul may be eying other advanced missile defense systems as a prelude to joining the U.S.-led regional missile defense network.

The minister later flatly denied related the news reports, saying South Korea won't be part of the U.S. regional missile defense program, said to unnerve Chinese officials.

Kim told reporters that the military has no plans to purchase THAAD.

Analysts say South Korea's military definitely wants to have THAAD or similar equipment that would enable it to better intercept North Korea's missiles.

THAAD is a land-based system designed to shoot down short- and intermediate-range ballistic missiles in their terminal phase using a hit-to-kill method.

It can cover far wider areas than PAC-III, aimed at low-flying missiles.

But a problem is money. South Korea's conservative president, Park Geun-hye, is facing a strong backlash at home for scaling back her welfare plans for elderly people due to budget constraints. (Yonhap News)