WASHINGTON - TWO airliners were one minute from colliding when one of the planes turned away from the other over the Atlantic this week, federal authorities said on Friday.

The National Transportation Safety Board said it was investigating an incident in which a Delta Air Lines flight and a Russian-registered passenger jet were heading toward each other on Thursday, when cockpit alarms went off.

The NTSB said the pilot of the Russian plane - a Transaero Boeing 747 - descended 200 to 300 feet to avoid Delta Flight 485.

The planes were at the same altitude - 33,000 feet over open ocean - and were '60 seconds apart from occupying the same airspace', said NTSB spokesman Peter Knudson.

Mr Knudson said the agency doesn't have enough information yet to know if the planes would have collided had evasive manoeuvres not been taken, or if they would have narrowly missed each other.

The two planes were about 290 kilometres north of San Juan when the near-collision occurred at about 6.30 pm local time.

The Delta Boeing 737 was headed from New York's Kennedy International Airport to Port of Spain, Trinidad. Details of the Russian plane's flight were not released.

'This was every bit the classic near miss,' said Doug Church, a spokesman for the National Air Traffic Controllers Association.

Mr Church said controllers in the Federal Aviation Administration's air traffic control center in San Juan told him the airliners were on intersecting flight paths at the time of the incident.

The NTSB said there were no injuries.

There was no FAA radar coverage in the area where the planes almost collided, as is the case over most open ocean.

The NTSB says aircraft are required to remain at least 15 minutes apart when flying through areas with no radar coverage.

Delta spokeswoman Betsy Talton would provide no further details of the incident. 'We are fully cooperating with the NTSB,' she said.

The NTSB also reported on Friday that it is investigating: -a near-collision of a commuter jet and a small plane on Thursday at Fresno Yosemite International Airport in California.

The two aircraft's wingtips came within 15 feet of each other during a nighttime landing. -- AP