The government said Friday that it believes North Korea pushed ahead with back-to-back launches of three mid-range ballistic missiles in recent days in order to stack up the regime's accomplishments ahead of its ruling party congress next week.

In a regular briefing, Seoul's Unification Ministry Spokesman Jeong Joon-hee said there could also be external factors behind the series of Musudan missile launches.

He said that North Korean leader Kim Jong-un may have ordered the launches conducted in a short period of time ahead of the ruling Workers' Party congress slated for next Friday.

The spokesman said that it's not appropriate to prejudge whether the North will wage another provocation but he stressed the government was closely monitoring the situation and stepping up defense readiness against all possibilities.

Regarding media reports that North Korea has practically blocked access to and from its capital Pyongyang ahead of the party congress, Jeong noted that the North customarily controlled its borders for key party events and birthdays of former leaders Kim Il-sung and Kim Jong-il.

He said the Seoul government understands that patrols have been bolstered in Pyongyang and other areas.