US Defense Secretary Robert Gates said Tuesday that the US wants to enlist Saudi Arabia in helping Pakistan stave off extremist threats from militants advancing on Islamabad. "Saudi Arabia clearly has a lot of influence throughout the entire region, and a long-standing and close relationship with Pakistan," Gates said. Gates, the senior US defense official, arrived in Riyadh on Tuesday afternoon following morning meetings in Cairo with Egyptian President Hosni Mubarak and Defense Minister Hussein Tantawi. Gates was in the Mideast as Pakistan and Afghanistan's leaders arrived in Washington to meet with US President Barack Obama. The defense secretary echoed the Obama administration's goal of enlisting both South Asian nations as full-fledged US allies in the fight against the region's militants.