VILNIUS, May 23 (Reuters) - Lithuania on Sunday called for European Union countries to jointly recommend that planes avoid Belarusian airspace, after a Ryanair flight was forced to land in Minsk and an opposition activist on board detained.

The proposal for a joint declaration will be put forward at a meeting of European leaders on Monday and will include a call to recognize the incident as a violation of International Civil Aviation Organisation rules, the foreign ministry said.

Lithuania has also asked its EU allies to summon Belarusian ambassadors and to protest against the use of military aircraft to divert planes.

"This is a brutal affront against all (the) EU," Lithuania's foreign minister Gabrielius Landsbergis said in a statement. (Reporting by Andrius Sytas in Vilnius; Editing by Alexander Smith)