WASHINGTON (AFP) - US President Barack Obama warned on Tuesday that his Egyptian counterpart Mohamed Mursi has a "responsibility to protect" the democratic principles advanced by the 2011 uprising.

Mr Obama "welcomed President Mursi's commitment to serving as a president for all Egyptians, including women and people of all faiths," the White House said, in a statement describing a phone call between the two leaders.

Mr Obama "emphasised President Mursi's responsibility to protect the democratic principles that the Egyptian people fought so hard to secure," it said, referring to the uprising that brought down longtime autocrat Hosni Mubarak.

"President Obama encouraged President Mursi, and all political groups within Egypt, to work to build consensus and advance the political transition." The two leaders also discussed the importance of implementing economic reforms in Egypt "that have broad support and will promote long term growth," and Mr Obama "welcomed" Egypt's contribution to regional peace and security.

The National Salvation Front, an umbrella opposition group, has vowed to boycott upcoming parliamentary elections - saying their transparency cannot be guaranteed - and has refused to join a national dialogue with Morsi.

Mr Mursi, who hails from the Muslim Brotherhood, became Egypt's first-ever elected leader last year but has come under withering criticism from opponents who accuse the Islamist movement of engaging in a power grab.

The NSF organised massive protests against Morsi in November and December after he adopted now-repealed powers that shielded his decisions from judicial review.

But the anti-Mursi protests have slowed since he pushed through an Islamist-drafted constitution in a December referendum, with the mass rallies giving way to smaller and often violent protests.

The White House said Secretary of State John Kerry is to visit Egypt on March 2 and urge "Egyptians to work together to build their democracy and promote economic stability and prosperity."