Bush offers $770m for food crisis

George W Bush has offered $770m  in international food aid to help ease the effects of surging food prices that have sparked riots in some countries.

The US president said he was asking Congress to approve his request.

The White House has come under intense pressure to step in as high food and petrol prices have squeezed poor families both at home and abroad.

The global crisis has sparked rioting in several developing countries, with the threat of worse to come.