Seoul, Aug 6 (IANS): Major highways in Seoul were partly closed on Thursday, with the first flood alerts issued after nine years, as heavy rains have increased the water level of the Han river that flows through the South Korean capital city.

Several sections of the Dongbu Urban Expressway, Seoul Inner Loop, Olympic-daero and Gangbyeon Northern Highway have been closed to traffic due to the inner city river's increased water level, reports Yonhap News Agency.

As heavy rains continued to batter the country's metropolitan and central regions, authorities opened the floodgates of Soyang River Dam and Paldang Dam a day earlier.

Meanwhile, the water level over Jamsu Bridge reached a record high level of 11.3 metres , completely submerging it.

The previous highest point was 11.03 metres posted in the July monsoon in 2011, according to the Han River Flood Control Center.

A total of 11 of Seoul's 25 wards, including Yongsan, Gangnam, Seocho and Mapo, are at risk of flooding because of the river's swelling water level, according to authorities.

At least 16 people have been killed in rain-related incidents so far, while over 15 remained missing as of Thursday and more than 1,600 people were displaced from their homes.