Three people were killed and scores others injured when a strong 6.1 magnitude earthquake rocked Costa Rica on Thursday, causing widespread panic and damage. "Today is a day of mourning for Costa Ricans, because the earthquake killed three people, two children and a woman," said President Oscar Arias at a joint news conference with the head of the National Emergency Commission. Police and neighbors found the bodies of two sisters who had been selling sweets near the epicenter, near the Poas volcano, one of Costa Rica's main tourist attractions, after they were killed by a landslide caused by the quake. The woman died of a heart attack. The quake injured 208 people, damaged some 42 communities as well as electricity networks, and cut off some 300 tourists in a luxury hotel near Poas, according to emergency services. The US Geological Survey (USGS) said the quake measured 6.1 on the moment magnitude scale, revising down an initial figure of 6.2. The quake, which hit at 1:21 pm (1921 GMT) some 35 kilometers (22 miles) northwest of the capital, shook water out of swimming pools and witnesses said they had not felt such a strong tremor in 30 years.