The densely populated centre of government, business and finance is home to 9.4 million people, with an additional 1.4 million who work and go to school there each day.
Oh has adopted a hardline position against North Korea, arguing that the South must possess its own nuclear weapons as the only way to neutralise the threat from Pyongyang.
However, South Korean President Yoon Suk Yeol has ruled out owning nuclear weapons, making it a priority instead to bolster a military alliance with the United States and restore security ties with Japan.
The drills came on a day that South Korea imposed new sanctions on eight North Koreans linked to nuclear and missile programmes.
The neighbours have clashed at sea and one of the South’s islands was bombed by the North, killing scores on both sides, but there has been no direct attack on Seoul since the end of the Korean War in 1953.
This month’s test of the North’s latest ballistic missile followed November’s successful launch of its first military spy satellite, while a constitutional revision in September enshrined the use of nuclear weapons as a national defence policy.
Source: CNA
