In South Africa about 200 supporters of the ruling African National Congress demonstrated in Cape Town on Thursday with placards calling for "Free Palestine".
The embassies in South Africa, Kenya, Tanzania, Mauritania, Nigeria, Senegal and Djibouti closed this morning.
A spokesman at the US embassy in Nairobi told the BBC the closures would be reviewed on a day-to-day basis.
The US embassies in Kenya and Tanzania were both bombed on 7 August 1998 in attacks which the US blamed on Islamic militant Osama bin Laden.
More than 220 people, mostly Kenyans, were killed in the explosions, and more than 5,000 wounded.
Protests
On 6 October more than 10,000 members of a Nigerian Islamic movement staged a demonstration in the northern city of Kano burning US and Israeli flags and calling for the government to cut diplomatic links with Israel.
In South Africa about 200 supporters of the ruling African National Congress demonstrated in Cape Town on Thursday with placards calling for "Free Palestine".
President Thabo Mbeki condemned what he termed Israel's "excessive and disproportionate" use of force against Palestinians.
In the Mauritanian capital Nouakchott more than 2,000 demonstrators on Thursday demanded the government break diplomatic ties with Israel.
Mauritania supported Iraq in the Gulf War in 1991 and only established relations with Israel in 1999.
US fears
A US warship in the Gulf of Aden was bombed in a suicide attack on Thursday which some US officials have blamed on Osama bin Laden.
In 1998 the US launched a cruise missile attack on a factory in the Sudanese capital Khartoum in retaliation for the embassy bombings.
It claimed the factory was involved in the production of chemical weapons and was linked financially to Mr bin Laden.
The owner is suing the US Government for compensation saying the allegations were totally without foundation.
Anti-American sentiment ran high after the attack.
American involvement in the Gulf War also prompted high levels of anti-American feeling in a number of African countries, particularly Nigeria, Niger and Senegal.