U.S. Ambassador Brian E. Carlson is among foreign officials offering congratulations to Latvia on the result of the Sept. 20 referendum on joining the European Union.

Carlson sent a letter to Prime Minister Einars Repše noting that the United States has been a strong supporter of EU enlargement as force for stability and prosperity in Europe, according to a press release from the U.S. Embassy in Rīga.

More than 1 million Latvian citizens participated in the referendum, with 67 percent saying “yes” to Latvia joining the EU. A total of 10 nations—including Latvia, Estonia and Lithuania—are expected to join next year, boosting the EU to a total of 25 members.

Other early congratulatory messages have been received by President Vaira Vīķe-Freiberga from political leaders in Austria, Finland and France, according to the president’s press office.