Experts have raised doubts about whether a loud boom and a gaping crater found in Nicaragua's crowded capital Managua this weekend were caused by a meteorite, as the government has said.

The impact near the international airport did not cause any known injuries, but it did leave a crater measuring 12 metres across and was felt throughout the capital.

The US National Aeronautics and Space Administration on Monday said that while a meteorite could not be ruled out, the lack so far of any eyewitness accounts of a fireball lighting up the nighttime sky outside Managua on Saturday suggests something else was likely behind the event.

Bill Cooke, head of NASA's Meteoroid Environment Office, estimated that the crater would have been created by a blast of roughly an energy equivalent of 1 ton of TNT.

NASA said in a statement that a meteor capable of that would have created a ball of flame visible over a wide area. About 1.5 million people live in the Nicaraguan capital.

"For something to produce a hole in the ground that big, it would have generated a very bright fireball. And nothing was reported ... despite the population," Cooke said. "So I'm very sceptical."

Nicaraguan authorities believe it was a piece of the small asteroid dubbed "2014 RC," which passed very close to Earth and was estimated by astronomers to be about 20 meters big, or the size of a house.

'Fascinating event'

Government officials and experts visited the impact site on Sunday.

One of them, William Martinez, said it was not yet clear if the meteorite burned up completely or if it had been blasted into the soil.

"You can see mirror-like spots on the sides of the crater from where the meteorite power-scraped the walls," Martinez said.

Government spokeswoman, First Lady Rosario Murillo, said Nicaraguan authorities would be in contact with the US Geological Service to try to get more information about "this fascinating event" in the Central American nation, one of Latin America's poorest countries.

People who live near the crater told local media they heard a blast they took for an explosion, and that liquid, sand and dust were blown through the air, which smelled like something had burned.

There were no reported injuries because the impact was in a wooded spot, and flights at the airport were not affected.

Source: Agencies