SEOUL -- South Korean Prime Minister Han Duck-soo was reinstated in his position on Monday as the constitutional court rejected a motion by the parliament to impeach him.

Moon Hyung-bae, acting chief of the court, said the motion was rejected as five justices rejected it while one upheld it amid the dismissal opinion from the remaining two.

The nine-member bench currently has eight justices as one has yet to be appointed by the country's acting president.

Despite confirmation that Han's impeachment process was legitimate, the court said neither evidence nor objective materials identified his involvement in impeached President Yoon Suk-yeol's martial law imposition and insurrection.

The court said Han's refusal to appoint constitutional court justices was unconstitutional, but it noted that evidence and objective materials failed to identify his intention to neutralize the ongoing deliberation on Yoon's impeachment.

With the rejection, Han was immediately reinstated as prime minister and acting president as the ruling took effect right after delivering the decision.

The impeachment motion against Han was passed by the opposition-controlled National Assembly on Dec. 27 last year following the impeachment of Yoon on Dec. 14 over his botched martial law imposition.

Choi Sang-mok, economy and finance minister who doubles as deputy prime minister for economic affairs, became the acting president in December last year after the impeachments of both the president and prime minister.

Yoon declared an emergency martial law on the night of Dec. 3, but it was revoked by the National Assembly hours later.