South Korean President Lee Myung-Bak convened a top-level security meeting on Wednesday to discuss growing tensions on the maritime border with North Korea ahead of the South's presidential election.
"Issues related to North Korea and other outstanding diplomatic and security matters will be discussed at the meeting," presidential Blue House spokeswoman Lee Mi-Yon told AFP.
Participants included the unification and defence ministers, the first vice foreign minister, the head of the National Intelligence Service and the senior presidential security advisor, she said.
On Monday, Lee warned of "growing threats" to the country's maritime security, posed by North Korea and regional territorial disputes over isolated island chains.
"We can never let our guard down even for a moment," he said during a visit to a coastguard base in the southern port city of Busan.
Weeks of repeated incursions by North Korean fishing vessels over the disputed Yellow Sea border culminated in the South Korean navy firing warning shots last week to push the boats back.
Pyongyang denounced the "shooting rampage" and threatened to respond with a "powerful strike of the (North's) front units which know of no limit."
South Koreans go to the polls to choose a new President in December, and there are fears that Pyongyang may be looking to instigate a clash that would overshadow the election process.
"Too many ships are violating the border too many times to call them a mistake," Unification Minister Yu Woo-Ik said this week.
"I just hope that such unusual... (border) violation is not planned," Yu said.