The National Transportation Safety Board says seven of the nine victims involved in Saturday's air collision over the Hudson River have been recovered.
All nine are presumed to have died when a small plane and a helicopter collided around noon Saturday.
During a press briefing Sunday evening, National Transportation Safety Board Chair Debbie Hersman confirmed the number of recovered bodies as divers continued their search for the two remaining victims and wreckage from the plane.
"The recovery efforts are focused on the Piper. Side scanning sonar revealed a number of promising targets," Hersman said. "Divers are working to confirm, then they will work on recovering the plane."
"It's changing every minute, there's 30 feet of water and two foot visibility and this is a part of the river, there's a lot of things under there, so they can find stuff and because of the visibility not know whether it's part of an aircraft or something that's been there for a long time underwater," said Mayor Michael Bloomberg.
Divers located the helicopter Sunday and used a crane to remove it from the water. Two bodies were entangled in the wreckage according to the New York City Police Department.
"The helicopter sustained significant damage," Hersman said. "They are going to be conducting further examination of the wreckage to determine what pieces might be missing once it's on the pier."
Published reports say the plane's pilot was Steven Altman, 60, and his passengers were his brother Daniel and nephew Doug.
Reports have identified the five Italian tourists who were on board the helicopter as Tiziana Pedrone, Fabio Gallazzi, Giacomo Gallazzi, Michele Norelli, Filippo Norelli. They have also identified the helicopter's pilot as Jeremy Clark.
NTSB officials say it's still too early to determine the exact cause of the collision.
"We're going to be looking at information about the aircraft, the age of the aircraft, maintenance of the aircraft, operations of the aircraft," Hersman said. "But we do have some early information from witnesses on scene helping us to put together the accident sequence. As well as some video or some still footage that I know that you all have seen. That kind of information is very helpful to our investigators."
Investigators say the plane took off from a suburb of Philadelphia, and then stopped at Teterboro Airport in New Jersey en route to Ocean City, New Jersey, while the helicopter took off from the 30th Street Heliport in Manhattan.
Shortly after take-off from Teterboro, air traffic control lost contact with the pilot.
Investigators say a pilot on the ground tried to warn both pilots that they appeared to be on a collision course, but they either didn't hear the warning or heard it too late.
The NTSB does not expect to recover a black box or cockpit voice recorder because they're not required on either aircraft.
Liberty Helicopters released a statement Sunday, saying they're cooperating with the NTSB and its investigative process. The Italian tourists were expecting to enjoy a 12-minute Big Apple Tour.
The NTSB says Liberty Tours had had eight accidents and one incident. In 2007, a helicopter plunged 500 feet into the Hudson. The pilot safely evacuated her seven passengers. The cause of that crash is still under investigation.
The agency is asking anyone with footage or pictures to come forward, and is warning anyone who comes across any wreckage not to touch it.
The Hudson River is a hotspot for sightseeing tours, but some pilots say the busy skyline can pose a challenge.
The Federal Aviation Administration says small planes like the ones that collided are restricted to flying below about 1,000 feet. Pilots flying at low altitudes are supposed to practice what's called "see and avoid."
"You look out for each other. In the case of the hudson river there's a radio frequency and everyone's supposed to self announce. You might say 'I'm taking off from 30th Street.' Or 'I'm at the Statue of Liberty heading northbound.' By listening in, you get a sense of where everyone else is and you can look out for the traffic," said Commercial Airline Pilot Ian Dutton.
"The FAA can't control every place and this could have happened over a cornfield or over the East River -- really any place where you see a lot of traffic in an area that's not positively controlled, you have to be careful," said Bloomberg.
The FAA has issued a temporary flight restriction for small aircraft over the Hudson. Only search, medical and law enforcement personnel will be allowed to fly below 2,000 feet in a three nautical mile radius while the hunt for bodies and wreckage continues.
Meanwhile, a report from the Federal Department of Transportation issued less than a month ago criticized the FAA for providing weaker oversight to "on demand" flight companies -- which are hired to fly aircraft that seat less than 30 people -- than for commercial airlines.
On-demand pilots are required to have a minimum of 500 hours of flight experience and a commercial license.
Commercial airline pilots need three times more experience and a more difficult air transport license.
On-demand flights also don't need warnings systems, cockpit voice or data recorders or in-flight radar systems. Many of the regulations governing the industry haven't been updated since 1978.
"We've seen a number of accidents involving charter operators or smaller aircraft," Hersman said. "We've also done some air tour investigations and we've made some specific recommendations from those."
Since 2002, the NTSB has made more than a dozen safety recommendations, none of which have been implemented.
The FAA says it is developing a new safety system for on-demand pilots, but it isn't scheduled to fully take effect for at least four years.
Saturday's collision wasn't the first time planes and helicopters have run into trouble over the Hudson.
Back in January, pilot Chesley Sullenberger safely splash landed US Airways Flight 1549 in the Hudson after a twin bird strike took out its engines.
All 155 people on board survived.