NEWTOWN, Conn. - A heavily armed gunman opened fire inside a Connecticut elementary school yesterday, killing 26 people, including 20 children, in the latest in a series of shooting rampages across the United States this year, US media reported. The gunman was dead inside Sandy Hook Elementary School in Newtown, Connecticut, state police Lieutenant Paul Vance told a news conference. Vance said the gunman killed 18 children and six adults at the school and two wounded children died later in the hospital. Another person connected to the suspect was found dead at a house in Newtown, bringing the death toll to 28. One of the dead was the shooter's mother, a teacher at the school, The New York Times reported, citing a law enforcement official. The New York Times also reported that the gunman killed himself at the scene. The suspected gunman entered the school as children were gathered in their classrooms for morning meeting. He was armed with four weapons and wore a bullet-proof vest, WABC reported. If confirmed, it would be one of the worst mass shootings in US history. The holiday season tragedy was the second shooting rampage in the United States this week and was certain to revive a debate about US gun laws. President Barack Obama, wiping away tears and pausing to collect his emotions, mourned the "beautiful little kids between the ages of 5 and 10 years old" who were killed. "As a country we have been through this too many times," Obama said, ticking off a list of recent shootings. "We're going to have to come together and take meaningful action to prevent more tragedies like this, regardless of the politics," Obama said in apparent reference to the influence of the National Rifle Association over members of Congress.