South Korea warned the Democratic People's Republic of Korea (DPRK) to stop provocative acts that raise unnecessary tension on the Korean peninsula, after the DPRK fired artillery shells into waters near the disputed maritime border, the government said.

Seoul's Ministry of Defense expressed in a message to the DPRK great concern over the firing and urged the DPRK to stop such acts and cancel its designation of no-sail zones, calling the recent move "provocative".

"Our military sternly warned (the DPRK) that we will resolutely deal with the DPRK's provocative acts and that the DPRK will be held responsible for all that is to follow," the defense ministry said in a statement.

The DPRK fired some 30 artillery shells starting 9:05 a.m. local time, which fell into waters north of the Northern Limit Line (NLL) within the range of no-sail zones declared by the DPRK a day ago.

NLL was fixed unilaterally by the U.S.-led United Nations Command after the 1950-1953 Korean War. South Korea holds the NLL as the de-facto western inter-Korean border, but the DPRK rejected the NLL and only recognized the demarcation line it drew in 1999, which was further south of the NLL.

South Korean military responded immediately by firing some 100 Vulcan cannons as warning shots, but there have been no casualties or injuries reported as the two sides fired into the air and not at each other.

"We would have made a counterattack if the shells flew toward the west (of the NLL into the South Korean territorial waters), but it landed on north side," Seoul's Yonhap News Agency quoted a senior military officer as saying.

The move came a day after the DPRK late Tuesday declared two no-sail zones until March 29 in waters near the disputed maritime border, where the latest naval skirmish between the two Koreas took place in November last year.