"We urge restraint," Catherine Ashton said ahead of a meeting of EU foreign ministers, called to discuss the unrest in the Middle East and North Africa, adding: "It's very important that the violence stops."
The protests in Libya, one of the world's major oil suppliers, started Feb 15 amid violent anti-government demonstrations across the Middle East. Riots are largely centered in the eastern cities of Benghazi, Bayda and Tobruk, but there are reports that unrest has been spreading to the west of the country.
On Saturday, several dozen people were killed in Benghazi when snipers reportedly opened fire at the crowd of mourners.
Ashton said the European Union supports pro-democracy reforms and plans to provide long-term financial assistance to the region.
The European Union's foreign policy chief is expected to pay a visit to Egypt Monday to hold talks with the country's authorities and opposition.