German chemicals group BASF said on Friday it closed its Egyptian operations on Thursday because of the violent political protests in the country.

"The safety of our employees has top priority. We are observing the situation carefully. All our employees are fine. The offices have been closed since yesterday," a spokeswoman for the world's largest chemical maker said.

BASF has about 100 employees based in Egypt, with offices in Alexandria and Cairo and a plant producing construction chemicals in Sadat City.

Of BASF's annual group sales of about 72 billion euros, the contribution from its Egyptian operations is in the low hundreds of millions.

Protests by supporters of ousted Islamist President Mohamed Mursi turned violent across Egypt on Friday as the Muslim Brotherhood staged a "Day of Rage", two days after an assault by security forces on its protesters killed hundreds.