By Nelson Renteria

SAN SALVADOR (Reuters) - A strong earthquake off the Pacific Coast of Central America shook the region on Thursday just as a hurricane barreled into the Caribbean coasts of Nicaragua and Costa Rica, but there were no immediate reports of any quake damage.

Emergency services in El Salvador said on Twitter it had received no reports of damage at a national level, but urged those living along the country's Pacific coast to withdraw up to 1 kilometer (0.62 mile) away from the shore.

The 7.0 magnitude quake, initially reported as a magnitude 7.2, was very shallow at 10.3 kilometers (6.4 miles) below the seabed, which would have amplified its effect.

Its epicenter was located some 149 km (93 miles) south-southwest of Puerto Triunfo in El Salvador, according to the U.S. Geological Survey.

The Pacific Tsunami Warning Center warned that tsunami waves of up to 1 meter (3 feet) could hit the Pacific coasts of Nicaragua and El Salvador after the quake, but later said that available data showed the threat had passed.

Nicaraguan President Daniel Ortega declared a state of emergency due to the quake and Hurricane Otto, which landed on the country's southeastern coast earlier on Thursday, his spokeswoman said.

"We were serving lunch to the lawmakers and the earthquake started and we felt that it was very strong," said Jacqueline Najarro, a 38-year-old food seller at the Congress in San Salvador. "We were scared."

Earlier on Thursday, the Category 2 Hurricane Otto hit land near the southeastern coast of Nicaragua, where thousands had already been evacuated away from vulnerable coastal areas and into shelters.

(Additional reporting by Sofia Menchu in Guatemala, Gustavo Palencia in Honduras and Ivan Castro in Nicaragua; Writing by Gabriel Stargardter; Editing by Sandra Maler and Simon Gardner)