Image caption Kim Jong-un took over from his father, Kim Jong-il, after his death on 17 December

North Korea says it will grant an amnesty for prisoners to mark the birthdays of two late leaders.

State news agency KCNA said that the amnesty would begin from 1 February, in honour of Kim Jong-il, who died last month, and his father Kim Il-sung.

No information was given as to how many prisoners would be released or who.

Amnesty International estimates as many as 200,000 people are being held in political prison camps around the country.

KCNA said that the amnesty embodied the "noble, benevolent and all-embracing politics of President Kim Il-sung and leader Kim Jong-il".

This year is being presented as the 70th anniversary of Kim Jong-il's birth and the centenary of his father.

Mr Kim died on 17 December of a heart attack. He had ruled North Korea - an impoverished nuclear-armed state with a dire human rights record - since the death of his father in 1994.

He is succeeded by his son, Kim Jong-un, who is in his late 20s and has little political experience.

North Korea last conducted a prisoner amnesty in August 2005, to mark the 60th anniversary of the end of Japanese colonial rule, and the one before that was in 2002.

It is not clear how many prisoners were freed on either occasion.

Last year rights group Amnesty International said that it believed prison camps inside North Korea were expanding.

Its findings were based on satellite imagery which showed that the size of the camps had grown considerably.

The group cited testimony from former prisoners describing a regime of torture, hunger and forced labour inside the camps.