"European integration has helped to realize centuries of hope for peace in Europe after unbridled nationalism and other extreme ideologies led Europe to the atrocities of two world wars... It is necessary that we all be actively involved in ideas for a peaceful and integrated Europe. The 2019 elections are extremely important. It is you, European citizens, who will decide in which direction the European Union will develop," the letter says.
"We invite all European citizens entitled to vote to participate in the European Parliament," it continues
"We are all Europeans. For many people in Europe, especially young people, European citizenship has become their second identity. They love their villages, towns, counties or nations and at the same time civic an active European identity does not create contradictions.
"In these months, the EU faces more serious challenges than ever before... For the first time, a Member State is planning to withdraw from the EU. At the same time other Member States require greater integration into the EU or the euro area, or Europe at different speeds.
"The views on these issues differ between the citizens and governments of the EU Member States, as they do among the heads of state. However, we all agree that European integration and unity are
essential and that we want to continue European cooperation in the form of this Union.
"We want a strong and integrated Europe. That is why we need a strong EU - a Union with shared institutions, a Union which is constantly reviewing its work with a critical view and able to reform, a Union that relies on its citizens and Member States as a solid foundation. This Europe needs a dynamic political debate on the best way forward," it says.
"Our united Europe needs a strong vote from its citizens. So we invite you to exercise your voting rights. It is a vote on our common European future."
The elections to the European Parliament take place in Latvia on May 25.