The Gulf state of Kuwait on Wednesday urged its citizens in Egypt to leave "at the earliest" and warned against travel to the country after President Mohamed Morsi rejected an ultimatum by the army, amid mass protests and deadly clashes.

"All Kuwaitis present in Egypt must leave at the earliest due to the developments and events in various parts of the country," the official KUNA news agency cited ambassador Rasheed al-Hamad as saying.

He also called on Kuwaitis to delay trips to Egypt due to the "unstable situation".

Kuwait becomes the first Arab country to issue a travel warning to Egypt, where supporters and opponents of embattled Morsi clashed during the night in the capital Cairo, leaving more than 20 people dead.

Thousands of Kuwaiti students are studying at Egyptian universities while tens of thousands of Kuwaiti tourists normally visit Egypt every year.