The U.N. refugee agency said Friday it feared that Syrian war exiles in Egypt could get caught up in its spiraling crisis, amid international condemnation of the bloody military crackdown.

"We are watching the situation very closely," UNHCR spokesman Adrian Edwards told reporters.

Hundreds of Muslims demonstrated in Indonesia and Malaysia Friday against a crackdown on the protest camps of Egypt's Islamists which left almost 600 people dead.

It came as Cairo braced for more protests after supporters of Mohammed Morsi, ousted as president in a military coup last month, called for a "Friday of anger", and the U.N. urged "maximum restraint" from all sides.

Germany on Friday "condemned in the strongest terms" the escalation of deadly violence in Egypt and urged all sides to avoid further bloodshed and return to dialogue.

The foreign ministry meanwhile widened its travel alert from Cairo and parts of the Nile River Delta to all of Egypt, including Red Sea tourist resorts, advising German citizens to stay away.

The European Union has said top officials from its 28 members will meet Monday to review the crisis in Egypt, where a military crackdown has left hundreds dead.

The meeting will look at the situation in Egypt ahead of a possible meeting of EU foreign ministers, Catherine Ashton's European External Action Service said on Twitter.

Cairo has cancelled naval exercises with Turkey scheduled to take place in October to protest Ankara's "clear interference" in Egypt's domestic affairs, the foreign ministry said on Friday.

The measures were in "protest at the unacceptable Turkish statements and actions which represent a clear interference in Egypt's domestic affairs and stand against the will of the Egyptian people," the ministry said in a statement.

French President Francois Hollande and German Chancellor Angela Merkel plan to discuss the Egypt crisis in a telephone call at 1200 GMT Friday, a diplomatic source said.

Hollande warned Thursday of the threat of "civil war" in Egypt, after a crackdown by security forces on supporters of ousted Islamist President Mohammed Morsi left nearly 600 people dead.

Turkey's clout in the Middle East is taking a beating with the brutal sidelining of Egypt's Muslim Brotherhood derailing Ankara's hopes to lead a regional surge of Islamist political power, analysts say.

Turkey's ruling Justice and Development Party (AKP) was an early supporter of the 2011 uprising that ousted President Hosni Mubarak and subsequently nourished close ties with the Muslim Brotherhood.

Egypt's Islamists called for a "Friday of anger" in Cairo after nearly 600 people were killed following a crackdown on their protest camps, as the U.N. urged "maximum restraint" from all sides.

"Anti-coup rallies... will depart from all mosques of Cairo and head towards Ramsis square after (traditional Friday) prayer in 'Friday of Anger'," Muslim Brotherhood spokesman Gehad al-Haddad wrote on Twitter.

Egypt's president on Friday suggested U.S. President Barack Obama's condemnation of a deadly crackdown on Islamists may "encourage violent armed groups".

"The presidency fears statements not based on facts may encourage violent armed groups," it said in a statement responding to Obama's condemnation of Wednesday's carnage when police moved to disperse Islamist protest camps.

The Argentine president of the U.N. Security Council urged all parties in the crisis in Egypt to exercise "maximum restraint" Thursday, following an emergency meeting in New York.

Argentine Ambassador Maria Cristina Perceval said that the Council's 15 member states had regretted the loss of life in Cairo, called for an end to the violence and spoke of the need to advance "national reconciliation."