A least seven people have been killed in overnight clashes between the police and supporters of Egypt's ousted president, Muhammad Morsi.
Senior Health Ministry official Khaled el-Khateib said on July 16 that more than 260 people were injured in the violence that broke out late on July 15.
He said the clashes continued early on July 16 in many parts of Cairo.
Muhammad Sultan, head of the capital's emergency services, told Reuters news agency that two people were killed at a bridge in central Cairo and five more in the Giza district.
Security forces have reportedly arrested more than 400 people for allegedly provoking the unrest.
Thousands of supporters of Morsi's Muslim Brotherhood movement are protesting to demand his reinstatement.
He was ousted by the military on July 3 after days of mass opposition protests.
On July 15, U.S. Deputy Secretary of State William Burns held talks with Egypt's interim government and military leaders.
Burns also said during a visit to Cairo on July 15 that Washington is "deeply committed to Egypt's democratic success and prosperity" and that "only Egyptians can determine their future."
Burns made the remarks after talks with Egypt's interim president, Adli Mansour, and Defense Minister Abdel Fattah al-Sissi, the architect of the military ouster of Islamist President Muhammad Morsi.
Burns is the first senior U.S. official to visit Egypt since Morsi's ouster on July 3.
Burns told journalists in Cairo that Washington would "stand behind certain basic principles" for Egypt, including the protection of "human rights and the rule of law."
"The United States remains deeply committed to Egypt's democratic success and prosperity," Burns said.
"We want a strong Egypt -- an Egypt which is stable, democratic, inclusive, and tolerant; an Egypt which addresses the needs and respects the rights of all of its citizens. That is the Egypt that Egyptians deserve, that is the Egypt that can lead the rest of the region into a better future."
Burns also said the United States would not favor any particular personalities or parties.
He was scheduled to stay in Cairo on July 16 for more talks with Egyptian officials.
There was no word on whether he would meet with members of the Muslim Brotherhood, the party of the ousted Morsi.
Based on reporting by AP and Reuters