Seoul, Dec 13 (IANS): South Korea expressed deep concern about a series of occurrences in North Korea, including the execution of Jang Song-Thaek, who was married to North Korean leader Kim Jong Un's biological aunt, Seoul's unification ministry said Friday.

"The government is closely monitoring the series of incidents, which are happening in North Korea, with deep concerns," unification ministry spokesman Kim Eui-do said in a statement.

Kim said South Korea would be in full readiness against all possibilities in North Korea, adding that it would closely consult with its allies and related countries, reports Xinhua.

The statement came after Kim Jang-soo, chief security adviser to President Park Geun-hye, held a national security policy coordination meeting with ministers of defence and unification as well as intelligence agency head after Jang's execution was announced.

Jang, 67, uncle of Kim Jong Un and widely viewed as the North Korea's number two man, was executed Thursday immediately after the Special Military Tribunal convicted him of committing "unforgivable crime as traitor".

The deposed senior general, who was vice-chairman of the National Defence Commission and secretary of the Workers' Party of Korea (WPK) administration department, admitted at the trial that he had premeditated a coup against Kim.

Jang was stripped of all posts and titles for "anti-party and counter-revolutionary crime" after an enlarged meeting of the Political Bureau of the WPK Central Committee Sunday.