The National Intelligence Service also assessed as "premeditated" the North's recent artillery firing drills on an inter-Korean border island in the Yellow Sea.
On Thursday, the North fired two short-range projectiles in a row from a super-large multiple rocket launcher from its eastern town of Yeonpo into the East Sea. It marked the 13th major weapons test by the North this year.
"North Korea apparently intended to give a warning message to the US and South Korea that it can return to the past (pattern of behavior) if it fails to achieve its goal from dialogue with Washington by the end of this year," the NIS was quoted as saying by lawmakers.
North Korea has pressed the US to put forward a new proposal on concessions by its year-end deadline amid stalled denuclearization talks between the two nations.
Earlier this month, the North unveiled that Washington proposed holding dialogue in December, but Pyongyang insisted that it is willing to engage only if Washington first unveils a fundamental solution to resolve the nuclear impasse.
Washington and Pyongyang resumed negotiations in Sweden last month after months of stalemate, but the talks broke down, with the North accusing the US of failing to come up with a new proposal. The North wants sanctions relief and some economic concessions from the US in exchange for its denuclearization efforts.
When asked about the possibility of a North Korea-US summit, the NIS said, "The chance is always there, but it is hard to pinpoint the timing."
As for Pyongyang's artillery firing drills on Nov. 23, the spy agency viewed them as a violation of an inter-Korean military deal reached in September last year, but not of an armistice agreement that halted the 1950-53 Korean War.
South Korea lodged a strong complaint with North Korea on Tuesday over its firing drills on Changrin Islet just north of the de facto western maritime border.
The NIS added that it expects the North to continue its provocative acts in "various formats."
The agency, meanwhile, said satellite imagery has shown a slight increase in the movement of vehicles and equipment at North Korea's Dongchang-ri missile launch site on the west coast.
The NIS said it is too early to judge that the vehicle movement portends a missile launch. (Yonhap)