Three anti-apartheid activists who escaped from custody to the U.S. consulate in Johannesburg have rebuffed a government offer to walk free, saying they will stay to highlight South Africa's political detentions.

The group issued a statement through their lawyer on Wednesday, calling their action "a plea to all South Africans and the international community not to allow the plight of political detainees to be forgotten."Earlier, the government said the three men - Murphy Morobe, Mohammed Valli and Vusi Khanyile - were in no danger of arrest if they left the Johannesburg consulate, which is legally U.S. territory and beyond South African jurisdiction.

But lawyer Krish Naidoo told reporters he had not received the government's assurances and the three would remain in the consulate for the time being.