San Jose - At least five people, among them three children, were killed after an earthquake with a magnitude of 6.1 on the Richter Scale shook Costa Rica, local media reported Friday.

More than 300 people were injured and scores remained missing after the quake, which took place on Thursday at 1.21 pm (1921 GMT) with an epicentre about 35 kilometres north off the capital San Jose.

Numerous subsequent tremors up shook the country up into the morning hours of Friday. More than 1,000 residents in Costa Rica remained shut off as roads remained impassable.

About 200 tourists remained trapped at the La Paz Waterfalls near the 2704-metre high Poas volcano, where the quakes had prompted mudslides.

Many houses were damaged especially in the town of Alajuela, rescue workers said. The quake prompted panic in the capital, as residents fled their houses to seek safety outside in streets and squares. (dpa)