WASHINGTON - Scrutiny of an air traffic controller's actions, including whether a phone call may have distracted him, intensified on Friday as investigators released new details about the deadly collision of a small plane and a tourist helicopter over New York's Hudson River last week.

Disclosures about how controllers handled the Piper PA-32 aircraft over a period of minutes also sparked an open controversy between safety regulators and accident investigators, prompting an unusual airing of sensitive information early in a high profile investigation.

Five Italian tourists in a helicopter, two passengers in a small plane and the two pilots died on Saturday when their aircraft collided and plunged into the river that separates New York and New Jersey. There were no survivors.

The National Transportation Safety Board, which is leading the investigation, suggested a controllers' personal phone conversation during the flight complicated attempts to warn the Piper pilot of the tourist helicopter and other aircraft in the area.

The Teterboro tower controller, who was engaged in a phone call at the time, did not advise the pilot of the potential traffic conflicts shortly after takeoff, the safety board said in a written update of the investigation released to reporters.

He did try to raise the pilot on his radio about the traffic up ahead after controllers at nearby Newark airport asked him to do so, safety officials said. The pilot did not respond.

NTSB and FAA investigators agree that the Teterboro controller, who was not identified and has been suspended for making the personal call while on duty, followed correct procedure by handing off radio control of the Piper to Newark on a different frequency as the plane reached the Hudson.

At that point, the FAA said the Teterboro controller's main responsibilities were over.

But the NTSB said he should have advised the Piper pilot of traffic over the river a full 40 seconds after technically relinquishing control of the plane.

Controllers are not obligated to direct pilots at low altitudes over the Hudson, but they are expected to warn them of any dangers when they become aware of them. The FAA on Friday convened a task force to review those rules.

The FAA had no comment on the safety board report, and stood by a statement made on Thursday that there was no evidence the controller's actions, including the phone call, contributed to the collision.

The controller's union, the National Air Traffic Controllers Association, said it was premature to suggest the controller's call had anything to do with the accident.

Union officials said the Piper pilot did, in fact, acknowledge the Teterboro handoff to Newark but did not respond to warnings after that.

They also said the river-area traffic was not immediately visible to the Teterboro tower radar. Regulators say radar images over the Hudson can be unreliable at times.

The controller continued to do his duty throughout what was going on, Ray Adams, a union spokesman based at the Newark tower, told reporters in a conference call Friday night.

(Editing by Vicki Allen)