Lebanon's Interior Minister Hassan Sabeh has resigned after rioters set fire to the Danish consulate in Beirut and damaged property in a Christian area of the Lebanese capital.
Up to 30 people were injured in the rioting which was sparked by publication in Denmark of cartoons of the Muslim prophet Mohammed.
Meanwhile, Syria has stepped up security at diplomatic foreign offices following criticism for failing to protect the Danish and Norwegian embassies from attacks in Damascus.
The Organisation of the Islamic Conference has condemned the attacks, describing them as deplorable and detrimental to the image of Islam.
Denmark and Norway have accused Damascus of failing to provide protection, despite calls for help, and they have urged their citizens to leave Syria.
A Danish MEP, Jens Pitt-Abonda, said the Syrian government had failed Denmark's ambassador.
The White House had said such protests could not have taken place without the support of the Syrian government.
The Syrians say that they were unable to stop the attacks.
Iran has meanwhile recalled its ambassdor in Copenhagen and militant groups in Iraq have called for attacks on Danish troops in the country to support the American and British forces.
The cartoons were originally published in a Danish newspaper, but have been reprinted elsewhere in Europe.