Saudi Arabia surprised the Bush administration by returning Sharif to Pakistan Sunday following years of exile in the kingdom.
Sharif is a top contender for prime minister, a situation officials in Washington reportedly view with disdain.
Bush administration officials see Sharif as too close to Islamists in Pakistan and they fear his tenure would degrade the economic and social reforms spearheaded by Pakistani President Pervez Musharraf, The Wall Street Journal said Thursday.
Officials in the United States and Pakistan reportedly see the move by Saudi Arabia as an attempt to insert itself into Pakistani affairs as Musharraf's power is diminishing.
Saudi Arabia favors Sharif returning to power, seeing his platform more compatible with theirs.
Saudi officials responded to criticisms saying it was equitable to return Sharif to Pakistan when officials in the United States and Pakistan aided the return of another former prime minister, Benazir Bhutto, in October.
Musharraf ousted Sharif in 1999 in a bloodless coup. Sharif agreed to exile in Saudi Arabia in exchange for amnesty.