(Reuters) - A magnitude 7.1 quake struck nearly 250 km (155 miles) northwest of Puerto Maldonado, Peru, in the early hours of Friday at a depth of 610 km, the U.S. Geological Survey said.

There were no immediate reports of damage, though social media users said tremors had been felt across the country and as far away as Arica in northern Chile.

Two strong shocks struck Pucallpa, a Peruvian town northwest of the epicenter, according to Twitter postings by several residents.

No tsunami warning was issued by the Pacific Tsunami Warning Center, and Chile's fire service said on Twitter that the quake did not have the potential to generate one off the Chilean coast.

(Writing by John Stonestreet in London; Editing by Alison Williams)