Kellogg, Brown & Root, the engineering, construction, and services company, and its former parent, Halliburton, have agreed to pay a combined $579m to settle US criminal and civil allegations that KBR bribed Nigerian government officials to obtain contracts.

The fines, imposed by the US Department of Justice and the US Securities and Exchange Commission, make the largest combined settlement ever paid by US companies for violations of the 1977 Foreign Corrupt Practices Act. They are the second biggest fines ever imposed, after the $800m US settlement by Siemens, the German conglomerate.