SEOUL — Parliamentary staffers used sofas and fire extinguishers to block soldiers armed with assault rifles and night-vision goggles from entering South Korea's National Assembly to maintain martial law, closed-circuit television (CCTV) footage released on Wednesday showed.

Shortly after President Yoon Suk Yeol declared martial law on Tuesday night — the first time it had been imposed in the South in over four decades — helicopters ferried the heavily armed troops into the compound of the country's parliament, the footage showed.