HAVANA/CANCUN, June 8 (Reuters) - A historically strong earthquake struck off Cuba's northwest coast on Monday, according to official reports, shaking parts of Cuba, Mexico and Florida that are typically not prone to quakes.

The U.S. Geological Survey (USGS) measured the quake at a magnitude 6.1 at a shallow depth of 26 km (16 miles) and its epicenter 104 km west-northwest of Mantua, Cuba, about two to four hours by car from the capital Havana.

An earthquake this strong had not hit within 322 km (200 miles) of Monday's quake since 1880, when a 6.0 temblor hit near San Cristobal, Cuba, said Earle.

Authorities have not yet reported any major damage or casualties, but the quake spiked concern in Cuba, where decades of economic crisis have left buildings in severe disrepair. Ongoing widespread blackouts across the region have made communications difficult.

"It felt strong. I had never felt anything like that," said Yusmila Hernandez, 44, at her home in Pinar del Rio, in western Cuba.

"People ran outside, everyone scared. I can’t even explain it. It felt like no earthquake has ever felt here before," Hernandez said.

USGS reported that shaking was also felt in Florida. In Mexico, the quake was felt in the tourist hubs of Cancun, Playa del Carmen and Tulum on the country's Yucatan peninsula. Residents and workers in Cancun's city center, unaccustomed to strong quakes, evacuated buildings.

Emergency protocols were activated in Mexico's Yucatan and Quintana Roo states, but there were not yet reports of damage, the state's governors both said on social media. 

No tsunami warning or watch was issued after the earthquake, according to the U.S. National Weather Service.

(Reporting by Annet Rios, Ayose Naranjo and Dave Sherwood in Havana, Cuba; Paola Chiomante in Cancun, Mexico, and Brendan O'Boyle and Cassandra Garrison in Mexico City; Writing by Brendan O'Boyle; Editing by Chris Reese and Nick Zieminski)