Egypt's military ruler stressed the importance of good ties with the United States in a meeting with the government on Sunday, a message that could signal an attempt to ease a crisis triggered by an Egyptian probe targeting American democracy activists.

Nineteen Americans were among 43 foreign and local activists banned from travel and referred to criminal court on accusations of working for organisations operating in Egypt without proper licences and which had received foreign funds illegally. Washington asked Egypt to lift the travel ban on the U.S. citizens, some of whom have taken refuge at the U.S. embassy.

Both the White House and Congress have warned that the crackdown could threaten Cairo's $1.3 billion in annual U.S. military aid.

In Sunday's meeting with cabinet ministers who have spoken out in public against foreign non-governmental organisations, Field Marshal Hussein Tantawi emphasised "the importance of maintaining the established relationships between the U.S and Egypt, and strengthening them", according to a statement. The meeting was attended by Prime Minister Kamal al-Ganzouri, Minister of International Cooperation Faiza Abul Naga, Foreign Minister Mohamed Amr and the head of the Egyptian Intelligence Services Murad Mouwafi.

A source with knowledge of the meeting said Tantawi told his ministers to "strike a balance" in their public statements.

Tantawi discussed the case of the U.S. NGO workers on Saturday during a meeting with U.S. General Martin Dempsey, chairman of the Joint Chiefs of Staff and the first senior U.S. official to visit Cairo since the charges were brought.

An American student was also detained by Egyptian authorities on Saturday, along with an Australian journalist and their Egyptian translator, on suspicion they had distributed cash to workers and incited them to take part in a strike demanding an end to army rule.

(Writing by Marwa Awad; Editing by Alison Williams)