Two Nigerian cabinet ministers have resigned after being accused of stealing funds from the national treasury.

A presidential spokesman, Olusegun Adeniyi, said health ministers Adenike Grange and Gabriel Adukwu stepped down Tuesday.

The spokesman said the officials will, in his words, be better able to face the corruption charges without their ministerial duties.

The officials are accused of failing to return unspent funds from last year's health budget. They have not commented on the allegations.

Nigerian President Umaru Yar'dua says he has "zero tolerance" for corruption. He has pledged to support an end to legal immunity for top government officials accused of graft.

The anti-corruption group Transparency International consistently ranks Nigeria as one of the most corrupt nations in the world.

Some information for this report was provided by AFP and AP.