The South Korea-US alliance "transcends any particular president," a State Department spokesperson said Thursday, as the National Assembly is moving to vote on an impeachment motion against President Yoon Suk Yeol over his short-lived martial law imposition.

Principal deputy spokesperson Vedant Patel made the remarks, voicing expectation that the impeachment process will proceed in line with South Korea's Constitution.

"This relationship, this alliance, this partnership that we have with the Republic of Korea. It transcends any particular president or government on both sides of the Pacific Ocean," Patel told a press briefing, referring to South Korea by its official name.

"This is an alliance of partnership that has transcended Republicans, Democrats, different administrations in our government, and as (it) continues to be the same in the Republic of Korea," he added.

Calling the impeachment process an "internal" one, Patel reiterated Washington's expectation that it will be handled in accordance with the Constitution.

"We continue to support the rule of law and democracy in the ROK, which we think are the foundational pillars of our alliance," he said.

Patel also said that Washington was encouraged by the "democratic resilience" of South Korea during a "period of testing and "uncertainty," in an apparent reference to the National Assembly's passage of a resolution to overturn the martial law decree.

"We are continuing to expect that the Republic of Korea's democratic system and democratic process will prevail," he said.

Yoon declared martial law late Tuesday and rescinded the emergency order hours later following the legislature's passage of the resolution to withdraw the order. (Yonhap)