South Korea's conservatives dropped their presidential candidate on Saturday and reopened the nomination process, after the former prime minister decided to join the party to challenge the liberal frontrunner in an election just four weeks away.

South Korea’s embattled conservative party has taken the unprecedented step of nullifying its primary and replacing presidential candidate Kim Moon Soo with former Prime Minister Han Duck-soo just one week after Kim’s selection.

SEOUL (Reuters) - South Korea's presidential frontrunner said Seoul should not rush a trade deal with the United States and called for a coordinated response with other countries to U.S. tariffs, arguing that Washington risked isolation with its policy.