BRUSSELS - Leaders of the European Union (EU) on Friday expressed their deep shock on the shooting incident in the US state of Connecticut killing at least 28.

"It is with deep shock and horror that I learned this evening of the tragic fatalities in the shooting in Connecticut. Young lives full of hope have been destroyed," said European Commission President Jose Manuel Barroso in a statement.

"On behalf of the European Commission and on my own behalf, I want to express my sincere condolences to the families of the victims of this terrible tragedy," Barroso said.

EU foreign policy chief Catherine Ashton said in her statement "I would like to express my shock at the tragic shooting at the school in Connecticut today".

"My thoughts go out to the victims, their families and the American people at this difficult time," Ashton said.

The shooting incident at an elementary school in Newtown, the US state of Connecticut on Friday morning has left at least 28 dead, with most of them children.