Powerful Blast Injures at Least 35 in Prague A powerful blast believed to be a gas explosion ripped open an office building in the center of Prague on Monday, injuring at least 35 people and sending shockwaves through the Old Town tourist district. The blast shattered windows in the scenic area of charming streets and postcard-pretty buildings, sending glass flying. Authorities closed a wide area around the site and some tourists were stranded on street corners with baggage-loaded trolleys, unable to get into their hotels. Authorities said two or three people were still believed to be missing, but sniffer dogs searching the rubble had not indicated that anyone was buried and the prime minister said it appeared no one had died. An AP cameraman filming at the time of the blast said the physical impact could be felt on the famed 15th-century Charles Bridge over the Vltava River, which was packed with tourists. The explosion occurred on Divadelni Street at about 10 a.m., in one of a row of several-story tall brick buildings dating back about a century. The street was covered with rubble and police evacuated people from nearby buildings. "It's really immense and huge, almost like after an air assault or a bomb explosion," Prime Minister Petr Necas said after visiting the scene. So, if we really prove what we think right now, which is that nobody died, it was very lucky. Prague mayor Bohuslav Svoboda ruled out a terrorist attack, saying the blast was a gas explosion. Prague is a major tourist capital, visited every year by legions of students, backpackers and others from around the world. In 2012, a total of 5.4 million people visited, with a large majority from outside the country - many from Germany, Russia and the United States. Officials had estimated that up to 40 were injured, but Zdenek Schwarz, head of rescue service in Prague later narrowed that down to 35. He told reporters that 30 of the injured were taken to hospitals for treatment, two of them with serious injuries. He said five people were treated at the scene, some bandaged and with faces still bloody. Among the injured were two Portuguese women, another two women from Kazakhstan, a man from Slovakia and a German woman, although none of their injuries was serious, the rescue service said. City Hall spokeswoman Tereza Kralova said the cause of the incident will be thoroughly investigated and "we believe it won't negatively affect tourism." Windows in buildings located hundreds of meters from the blast were shattered, including some in the nearby National Theater, an ornate 19th-century structure that is one of the most important cultural institutions in the Czech Republic. "There was glass everywhere and people shouting and crying," Vaclav Rokyta, a Czech student, told the AP near the scene. The Faculty of Social Sciences of Prague's Charles University and the Film and TV School of the Academy of Sciences of Performing Arts are located next to the damaged building. Students had to be evacuated. I was in the bathroom, no windows, the door was closed. Honestly, if I had been in my bed I would have been covered in glass," said Z.B. Haislip, a student from Raleigh, North Carolina, who was in a nearby building. The road closures caused major traffic disruption and confused thousands of tourists. Rescuers were still searching the rubble, using sniffer dogs. Two or three people were still believed to be missing, firefighter spokeswoman Pavlina Adamcova said. The building likely belongs to the Air Navigation Services of the Czech Republic, said Richard Klima, spokesman for the state-run company that provides air traffic information for civil aviation in the country. Klima said about six other firms rented office space in the building. The Prague blast comes the day after a possible gas explosion ripped off the side of a five-story residential building in France's Champagne country, killing at least two people and injuring 14 others In 2006, another gas blast in Prague killed two men.