BEIJING, May 25 (Xinhua) -- China on Monday expressed "serious concern" over media reports on discussions by U.S. officials on the possibility of resuming nuclear tests, urging the United States to meet its "due obligations" under the Comprehensive Nuclear-Test-Ban Treaty (CTBT).

Some U.S. media outlets last Friday reported that U.S. national security officials discussed the possibility of resuming nuclear tests during an internal meeting held earlier this month, quoting senior U.S. government officials.

"We'd like to express serious concern over these reports," Foreign Ministry spokesperson Zhao Lijian told a press briefing when asked to comment on a related question.

Zhao said although the CTBT, an important pillar underpinning the international regime of nuclear arms control, has yet to come into effect, the nuclear test ban has become an international norm. "The treaty is of great significance in advancing nuclear disarmament, preventing nuclear proliferation, and safeguarding world peace and security."

The five nuclear powers including the United States have signed the treaty and made the commitment of "suspending nuclear testing," the spokesperson said, noting the United States has taken the lead in the total number of nuclear tests conducted so far.

"We'd like to urge the United States to meet its due obligations, abide by its commitments under the CTBT and earnestly uphold the treaty's purposes and objectives. The United States should contribute more to nuclear disarmament and the non-proliferation regime, rather than further tread down the path of undermining global strategic stability," Zhao added.