U.S. Secretary of State John Kerry on Wednesday urged Egypt's military to allow elections and for all sides to avoid further violence.

Denouncing the crackdown on supporters of ousted president Mohammed Morsi, Kerry urged a "peaceful, democratic way forward."

Egyptian vice president, Nobel laureate Mohammed ElBaradei, announced his resignation in a letter to the interim president on Wednesday seen by Agence France Presse.

The resignation comes after scores were killed in a crackdown by security forces on loyalists of ousted Islamist president Mohammed Morsi.

The United States on Wednesday strongly condemned Egyptian forces' bloody crackdown on protesters and denounced the imposition of a state of emergency.

White House spokesman Josh Earnest urged the Egyptian military to show restraint after a crackdown on supporters of deposed elected president Mohammed Morsi.

Egyptian military planes landed in the Sudanese capital on Wednesday, an Agence France Presse photographer said, as part of a regional aid effort for flood victims in the Khartoum area.

The five cargo aircraft brought blankets, emergency sheeting material and tents, the photographer said.

The teenage daughter of a senior Muslim Brotherhood leader was reported killed Wednesday as police cracked down on a Cairo camp set up by supporters of ousted president Mohammed Morsi.

Seventeen-year-old Asmaa al-Beltagui, daughter of wanted Brotherhood leader Mohammed al-Beltagui, was killed in clashes at the Rabaa al-Adawiya protest camp, Brotherhood spokesman Gehad al-Haddad said.

U.N. Secretary General Ban Ki-moon on Wednesday condemned a police crackdown on protesters in Egypt that he said had left hundreds dead and injured.

"In the aftermath of today's violence, the secretary-general urges all Egyptians to concentrate their efforts on promoting genuinely inclusive reconciliation," his spokesman Martin Nesirky said.

Qatar, a main backer of the Muslim Brotherhood, strongly condemned a bloody crackdown in Cairo on Wednesday by security forces against supporters of ousted Egyptian president Mohammed Morsi.

"Qatar strongly denounces the means by which peaceful protesters in Rabaa al-Adawiya camp and Al-Nahda square have been dealt with and which led to the killing of several unarmed innocent people among them," a foreign ministry spokesman said in a statement published on the official QNA agency.

Hundreds of angry supporters of ousted president Mohammed Morsi marched through Egypt's second city of Alexandria on Wednesday rioting and armed with wooden clubs, an Agence France Presse reporter said.

Chanting "Morsi is my president", the protesters set fire to car tires and tore down pictures of army chief Abdel Fattah al-Sisi, who was behind the Islamist leader's July 3 overthrow.

A veteran TV cameraman for Britain's Sky News was shot and killed while covering the deadly violence in Cairo on Wednesday, the channel said.

Mick Deane, a 61-year-old father of two, had worked at Sky for 15 years. He had been based in Washington and, for the past two years, in Jerusalem.

Iran condemned what it called a "massacre" in Egypt as police moved on Wednesday to clear protests in Cairo by supporters of ousted president Mohammed Morsi, Fars news agency reported.

The crackdown by Egypt's security forces on two protest camps in the capital quickly turned into a bloodbath, with dozens of people killed and scores injured.