U.N. Secretary General Kofi Annan called U.S. President George W. Bush Thursday to brief him on his recent trip to Africa and discuss an expansion of the African Union forces in Darfur, the White House said. White House spokesman Scott McClellan said in a press briefing that Annan expressed support for an expansion of African Union troops in Darfur from 3,000 to 8,000. Bush told Annan that the U.S. is in favour of NATO assisting in getting the troops in place, dpa reported. McClellan also said Annan described the positive impact these security forces already have on Darfur and how this could be amplified by adding additional troops. Both leaders also agreed on the importance of getting the government of Sudan and the rebels to the negotiating table. NATO defence ministers on Thursday gave the formal go-ahead to the setting up of a combined NATO and European Union coordinating cell in Addis Ababa for transporting African Union troops into Darfur. -- SP 2316 Local Time 2016 GMT