U.S. Secretary of State Hillary Rodham Clinton has congratulated Latvia on the 20th anniversary of its restored independence, which the country is marking May 4.

In a text and video message posted on the Department of State’s website, Clinton praised the Latvian Supreme Council’s historic decision on 1990 to formally break away from the Soviet Union. Indepedent Latvia was occupied by the U.S.S.R. beginning during World War II.

“That brave decision was backed by the will of the Latvian people, many of whom risked their lives to make sure that they defended independence,” Clinton said.

Latvia, she said, is an example to other countries.

“Today, your vibrant democracy is an inspiration to countries around the world that are now struggling themselves toward freedom,” Clinton said. “Your efforts to bring peace and stability to places torn by conflict and devastated by disaster are a testament to the spirit of the Latvian people.”

Clinton alluded to challenges Latvia has faced in the past two decades, and noted the country’s membership in the NATO defense alliance and the European Union.

“Rebuilding a nation after five decades of occupation is not easy, but you can be proud of what you have achieved in the last 20 years,” she said. “Membership in NATO and the European Union took patience and persistence, and they were richly deserved.”

Clinton noted the close diplomatic relations between the U.S. and Latvia.

“The United States is honored to call you a strategic ally and a close friend,” Clinton said, “and we look forward to working with you to meet the challenges of this, the 21st century.”

The video message can be viewed here.

Flights to and from Rīga International Airport resumed as of 9 a.m. local time April 20, the Latvian carrier airBaltic has announced on its Web site.

The airline listed flights to various locations as scheduled to depart, including Spain, Turkey, the Netherlands, Italy, Greece, Ukraine, Russia, Lithuania, Sweden and Norway.

Airspace over Latvia had been closed to passenger traffic since April 15, when a number of European countries restricted travel because of concerns about volcanic ash from Iceland. The Eyjafjallajökull volcano in south Iceland began spewing ash in late March. As it reached the jet stream, the ash traveled southeast toward Great Britain, Scandinavia and northern Europe.

By the morning of April 20 the ash over much of Europe had dissipated enough to allow some airlines to resume safe operations to some destinations.

The airspace restrictions stranded passengers in Rīga, as well as those trying to get back to Latvia from abroad.

Because of continuing concern about volcanic activity, travel is still restricted in parts of Great Britain, according to a notice on the Web site of London’s Heathrow Airport. While restrictions were lifted for three airports in Scotland—Aberdeen, Edinburgh and Glasgow—they remain in place for Heathrow, Stansted and Southampton. Britain’s National Air Traffic Services warned that another ash cloud could be forming as volcanic activity strengthens.

Passengers on airBaltic flights that were canceled, according to the airline’s Web site, may transfer to the next available flight or apply for a refund of unused tickets.

The International Air Transport Association, of which airBaltic is a member, on April 19 criticized European governments for their decision-making in the face of the ash cloud.

“We are far enough into this crisis to express our dissatisfaction on how governments have managed it—with no risk assessment, no consultation, no coordination, and no leadership,” IATA Director General Giovanni Bisignani said in a press release. European officials made their decision to close airspace based on theoretical models, not on facts, Bisignani said. The decision has cost airlines USD 200 million a day in lost revenue.