'I gather they don't speak English,' he said, adding the officials would 'help the families get through this difficult period.'

The helicopter operated by Liberty Tours had taken off from the 30th Street helipad for a sightseeing tour about noon, CNN reported.

The single-engine aircraft, carrying three people including one child, had taken off from Teterboro Airport outside New York City and was headed south to the New Jersey beach town of Ocean City.

Bloomberg noted that small aircraft and helicopters have flight corridors over the Hudson and East Rivers. While there is no legal requirement for radio contact and visual flight rules were in effect, he said it was common practice for pilots to use a radio frequency identified on all maps to make each other aware of their positions.

'It is a crowded busy area, and pilots who fly there are well trained and have practice,' he said.

It was not clear if the pilots were in radio contact with each other.