WASHINGTON: U.S. President Barack Obama congratulated Egyptian President-elect Mohammed Mursi by phone on Sunday, and also called the Islamist's defeated rival, Ahmed Shafiq, to encourage him to stay active in Egyptian politics, the White House said.

The two calls took place hours after Mursi was declared Egypt's first freely-elected president, sparking joy among Muslim Brotherhood supporters. Shafiq, a former air force commander, was the last prime minister of Egypt's long-time leader Hosni Mubarak.

"The president underscored that the United States will continue to support Egypt's transition to democracy and stand by the Egyptian people as they fulfill the promise of their revolution," the White House said in a statement about Obama's conversation with Mursi.

"The president emphasized his interest in working together with the new Egyptian president and all Egyptian political groups to advance the shared interests between the United States and Egypt," it said in a separate statement about the Shafiq call, saying Obama urged him to help unify the Egyptian people.

Earlier on Sunday, the White House described Mursi's victory as a "milestone" in Egypt's transition to democracy and urged the new leader to respect the rights of all Egyptians, including women and religious minorities.

Shafiq had promised to protect Egypt from being dragged back to the "dark ages" under Islamist rule.