North Korea's naval command on Thursday accused South Korean ships of violating its territorial waters in the Yellow Sea and warned that escalating tensions could lead to a clash.

The warning came two days after the hardline communist country fired short-range missiles in the Yellow Sea, the scene of bloody naval clashes in 1999 and 2002.

"The situation... has become so tense that a naval clash may break out due to such military provocations as the ceaseless infiltration of warships deep into the (North's) territorial waters," the state news agency KCNA quoted a naval spokesman as saying.

He accused the South's navy of sending more warships into the North's territorial waters since early September in an attempt to set the disputed sea border known as the Northern Limit Line (NIL).

The two Koreas have remained technically at war since their 1950-1953 conflict ended in a fragile armistice, rather than a peace treaty.

North Korea has never recognised theseaborderwiththeSouththat was drawn up by a US-led UN Command after the war, and it is a frequent flashpoint between them. Pyongyang puts the border at further south.