By Jack Kim and Ju-min Park
SEOUL (Reuters) - North Korean leader Kim Jong-un has named a hardline general who is believed to have masterminded an attack on South Korea to the post of Armed Forces Minister as part of a broad reshuffle of the military, South Korean officials said on Thursday.
Kim Kyok-sik's appointment as the Minister of People's Armed Forces marks a return to the top ranks of one of the world's biggest armies by a man who had previously been pushed aside by a rival who has since been purged.
"The reshuffle is part of loyalty test by First Chairman Kim Jong-un," a South Korean government official said.
A second South Korean official confirmed that Seoul believed a new minister had been appointed. There was no official announcement by Pyongyang and it was impossible to verify the reports.
Kim commanded the North's 4th Army Corps that was responsible for the bombing of a South Korean island in 2010. The attack killed four people in what was the first on a civilian area in the South since the 1950-53 Korean War.
North and South Korea remain technically at war as an armistice rather than a peace treaty ended the conflict.
Kim's military career also included working as a liaison officer with Syria, one of a few allies of the diplomatically isolated North, according to North Korea Leadership Watch, a website that specializes in tracking personnel there.
Syria and North Korea have close military ties and a ship carrying North Korean cargo that could be used to make missiles headed for Syria was stopped in May.
U.N. sanctions ban arms trade with North Korea and were imposed after the isolated state's 2009 missile and nuclear tests.
The second South Korean official said Kim Kyok-sik's appointment is the latest move in a military reshuffle that began earlier in the year with the purge of one of the highest ranking army men, Ri Yong-ho.
"It could be the most significant move after Ri's dismissal to strengthen his (Kim Jong-un's) grip on the military," the official said, speaking on the condition of anonymity.
The post of the Minister of Armed Forces is considered subordinate to the Army Chief of General Staff and its head of the Political Department.
But the appointment is indication of a top army general being rewarded for loyalty to the new leader as he tries to cement his power after taking over from his father Kim Jong-il who died in December last year, the officials said.
(Editing by Jonathan Thatcher)