U.S. Secretary of State Antony Blinken met South Korea's acting leader Choi Sang-mok in Seoul on Monday. Millions should prepare for disrupted travel and winter conditions as a fierce storm is set to bring ice, snow and freezing rain to much of the U.S.

Finance Minister Choi Sang-mok became on Friday South Korea's second acting president in two weeks, as lawmakers voted to impeach the current acting leader, Prime Minister Han Duck-soo, fuelling political uncertainty in Asia's fourth-largest economy.

Choi, 61, a veteran economic technocrat who has served for more than 30 years at the finance ministry, takes on an unprecedented role as successor to an impeached acting leader.