South Korea said Thursday that the U.N. Security Council is discussing comprehensive measures against the recent back-to-back missile tests by North Korea, apparently dismissing speculation that China might be hampering its swift action.

On July 9, the North fired off a submarine-launched ballistic missile off its east coast but it exploded in midair.

Pyongyang also test-fired three missiles on Tuesday in an apparent protest against a joint decision by Seoul and Washington to deploy an advanced missile defense system on the peninsula.

Both violated U.N. resolutions that ban the North from firing off ballistic missiles or testing related technologies.

The council, however, has not unveiled countermeasure in response to the SLBM test, raising speculation that China could be behind the delay as it might not be in a cooperative mood following the confirmation that Seoul and Washington agreed to deploy the Terminal High Altitude Area Defense system on South Korean soil.

China has opposed the THAAD deployment worrying that it could hurt its strategic security interests.

"The UNSC was preparing its response to the SLBM test when the North launched the three ballistic missiles. We understand that it is currently seeking to come up with countermeasures by taking into consideration both of the cases," Cho June-hyuck, foreign ministry spokesperson, said in a regular briefing.

"(We) are making necessary diplomatic efforts under close cooperation with our allies," he added.

 With regard to the speculation over China, he noted that Beijing joined the unanimous move by the council in March to adopt Resolution 2270 aimed at punishing North Korea for fourth nuclear test earlier this year, and that it has repeatedly renewed its commitment to faithfully implementing sanctions against Pyongyang.

"We expect that the UNSC will take action swiftly," he said. (Yonhap)