Foreign Ministry Alaa el-Hadidi said the criticism of State Department spokesman Sean McCormack "infringed on the rulings and independence of the Egyptian judiciary," the semi-official Middle East News Agency reported.
Egypt rejects any demand that conflicts with a ruling of the Egyptian judiciary, regardless of the reason, MENA quoted el-Hadidi as saying.
On Thursday, an appeal court rejected the appeal of Nour, 41, who was jailed for five years in December after being convicted of forging signatures on a petition to register his al-Ghad Party in 2004.
Nour, who was the runner-up to President Hosni Mubarak in last year's elections, claimed he was being prosecuted to eliminate him politically. And numerous Egyptian and international human rights groups had criticized the case, the AP reports.
Hours after the appeal was dismissed, McCormack told reporters in Washington: "The Egyptian government's handling of (Nour's) case represents both a miscarriage of justice by international standards and a setback for the democratic aspirations of the Egyptian people."