Police Commissioner Bheki Cele says South African intelligence officials are in touch with American security authorities regarding Tuesday's closure of US diplomatic offices in South Africa.

Cele insisted everything was under control. The US buildings closed include the fortress-like embassy in Pretoria and consulates in Johannesburg, Cape Town and Durban.

Embassy spokesperson Sharon Hudson Dean would not talk about the regional security warning they received.

She expected the missions to open on Wednesday.

Staying closed for longer could impact on preparations for next year's Word Cup and even affect bilateral relations.

Cele said things were happening and the issue was under control.

American helicopters last week killed an al-Qaeda operative in Somalia suspected of helping plan the 1998 bombing of US embassies in Nairobi and Dar es Salaam, killing 213 people.