Security forces fired teargas to disperse stone-throwing demonstrators near the US embassy
in Cairo late on Wednesday, some 24 hours after protesters scaled the walls and tore down the flag over a film insulting the Prophet Mohammad.
Similar protests in Libya
led to an attack that killed the US ambassador to the country and three embassy workers.
State news agency MENA said 14 people were injured in clashes.
Live television showed hundreds of demonstrators gathered at the embassy, where late on Tuesday around 2,000 protested outside after some illegally entered the compound, ripped down the flag and burned it.
Washington has a big mission in Egypt,
partly because of a huge aid program that followed Egypt's signing of a peace treaty with Israel in 1979. The United States gives $1.3 billion to Egypt's military each year and offers the nation other aid.
Clashes between security forces and protesters continued in side streets near the building into the early hours of Thursday.
Egypt's MENA said earlier Egypt had arrested four people after Tuesday's demonstration in which protesters blamed the film on the United States.
Security at American missions increased
Egyptian President Mohamed Morsi
said on Thursday he supported peaceful protests, but that it was wrong to attack people or embassies.
Speaking in a televised address after demonstrators angry at a film about Prophet Mohammad scaled the US embassy walls, he said: "Expressing opinion, freedom to protest and announcing positions is guaranteed but without assaulting private or public property, diplomatic missions or embassies."
At least one person was killed and five were injured after protesters angered by the film stormed the US Embassy in Sanaa, Yemen, on Thursday, AFP reported.
Witnesses said the demonstrators smashed windows of the security offices outside the embassy before breaking through the main gate of the heavily fortified compound in eastern Sanaa.
Security guards opened fire and there were reports of casualties on both sides.
It was also reported tha before storming the embassy compound, the demonstrators removed the embassy's sign on the outer wall and set tires ablaze. Once inside the compound, they brought down the US flag and burned it.
Meanwhile, an Iraqi militia that carried out some of the most prominent attacks on foreigners during the Iraq war threatened US interests in the country over the film.
"The offence caused to the messenger (Prophet Mohammad) will put all American interests in danger and we will not forgive them for that," Qais al-Khazali, leader of the Asaib al-Haq militia, said.
Also on Thursday, security has been increased at American missions around the world following Tuesday's attack.
President Barack Obama ordered increased security at US diplomatic missions overseas and vowed justice for the attack on the US consulate in Libya that killed the ambassador and three other people.