The Democratic People's Republic of Korea (DPRK) has rejected Seoul's conditional proposal for three summits between the two countries' leaders, a National Defense Commission spokesman said on Wednesday.

South Korea asked the DPRK to apologize first over the sinking of the South Korean warship "Cheonan" and the artillery shelling on the Yonphyong Island last year, the KCNA news agency quoted the spokesman as saying.

The government of Lee Myung-bak had repeatedly told the DPRK since April that it would no longer bring up the two incidents to make way for secret contacts to discuss issues concerning the summits, the spokesman said.

But when the two sides met secretly on May 9, South Korea said the two incidents need to be "wisely overcome" and asked for apology from Pyongyang, he added.

It is impossible to hold summits when South Korea continues its hostile policy against the DPRK, said the spokesman, noting that it is Pyongyang's firm standpoint.

South Korea has proposed holding summit meetings in late June, August and March next year as well as ministerial-level preparatory talks, according to the KCNA report.