The European Union Sunday condemned the raid carried out by Ecuadoran forces at Mexico's embassy in Quito to arrest graft-accused former vice president Jorge Glas, saying it was "essential to protect diplomatic immunity".

"The European Union condemns the violation of the... Mexican embassy that happened on April 5 and insisted on the importance of respect for the 1961 Vienna Convention on Diplomatic Relations," the 27-nation bloc said.

"Protecting the integrity of diplomatic missions and their personnel is essential to preserve stability and international order, promoting cooperation and trust between nations," it said in a statement.

Glas sought refuge in the Mexican embassy last December after an arrest warrant was issued against him for alleged corruption, in a move that Ecuadoran President Daniel Noboa's government branded an "illicit act".

Special forces equipped with a battering ram on Friday surrounded the embassy, and at least one agent scaled the walls, in an almost unheard-of raid on diplomatic premises that are considered inviolable sovereign territory.

"Any violation of the inviolability of the premises of a diplomatic mission violates the Vienna Convention and must therefore be rejected," the EU said.