WASHINGTON, May 4 (AFP) - US President Joe Biden on Thursday said weeks of urban fighting in Sudan "must end" and authorized potential new sanctions against those responsible for the bloodshed.

"The violence taking place in Sudan is a tragedy -- and it is a betrayal of the Sudanese people's clear demand for civilian government and a transition to democracy," he said in a statement. "It must end."

Clashes between rival factions began on April 15 and have killed an estimated 700 people, mostly in Khartoum and Darfur, according to the Armed Conflict Location and Event Data Project.

The chaos has sparked a large-scale evacuation of foreign citizens conducted by the militaries of several countries.

Biden said the bloodshed, "which has already stolen the lives of hundreds of civilians and began during the holy month of Ramadan, is unconscionable."

The United States joins "the peace-loving people of Sudan and leaders around the world in calling for a durable ceasefire between the belligerent parties."

Biden also signed an executive order on Thursday that broadens authority to impose sanctions on those responsible, although it does not name potential targets.

In his statement, Biden said those facing the sanctions are "individuals responsible for threatening the peace, security, and stability of Sudan; undermining Sudan's democratic transition; using violence against civilians; or committing serious human rights abuses."