The Han River, which runs through Seoul, was declared officially frozen on Sunday amid subzero temperatures.

The Korea Meteorological Administration (KMA) said it confirmed the season's first ice formation on the Han River Sunday morning.

The KMA declares the river as "frozen" only when it confirms ice between the Han River Bridge's second and fourth piers, a distance of about 100 meters.

This year's ice formation on the river was 16 days earlier than previous years and spotted for the first time in two years, as ice did not form on the river last year due to a warm winter.

It also marked the fourth earliest ice formation on the river in the 2000s.

Since the weather agency started observing ice formations on the river in 1906, the frozen period of the river is decreasing as the river remained frozen for over two months 100 years ago, but it stayed frozen for over one month just four times since 2000.