Investigators in France began examining Friday the flight data and voice recorders from the Ethiopian airliner that crashed earlier in the week, killing all 157 people on board.
The Boeing 737 MAX 8 crashed Sunday soon after takeoff from Addis Ababa, the second such crash involving the new Boeing model after a jet went down last October in Indonesia.
While officials from Ethiopia are officially leading the investigation, experts from France and the United States are assisting. The first results from the flight data and voice recorders could take several days.
Also Friday, U.S. President Donald Trump spoke by phone with Ethiopian Prime Minister Abiy Ahmed to offer his condolences for those who died on the flight.
"The president reiterated his sorrow over the loss of life and underscored America's commitment to work with the Government of Ethiopia a longstanding partner and friend of the United States and international civil aviation authorities to determine the cause of the crash," the White House said.
Prime Minister Abiy also "offered his condolences to the families and friends of the eight Americans killed and thanked President Trump for U.S. assistance in investigating the incident," the White House said.
Aviation investigators say they have found a piece of a stabilizer in an unusual position in the wreckage of the Ethiopian airliner. Sources familiar with the incident say that the position of the stabilizer was similar to that of the Indonesian Lion Air jet that crashed last October.
Satellite-registered data have shown that Ethiopian Airlines Flight 302 and Lion Air Flight 610 planes flew with erratic altitude changes — moving up and down by hundreds of feet — indicating that the pilots struggled to control the aircraft. In both cases, crews asked permission to return to the airports from where they had departed minutes after the flight took off.
The United Nations held a memorial in Geneva Friday to honor the 21 U.N. staff members who lost their lives in the plane crash. The U.N. staff was on its way to attend a major U.N. Environment Conference in Nairobi when the plane went down.
The director-general of the United Nations Office in Geneva, Michael Moller, said those who died are "all our heroes."
In New York, U.N. Secretary General Antonio Guterres attended a wreath laying service for the U.N. staff who died on the flight, saying "We come together in sadness and solidarity to pay tribute to our fellow U.N. family members."
The United States and more than 30 other countries have grounded the Boeing 737 Max 8 fleet after the Ethiopian air disaster. The Lion Air killed all 189 passengers and crew on October 29.
About 5,000 Boeing 737 MAX 8s are on order, signaling the company may face a financial struggle ahead.
Boeing said it supports the grounding of its planes as a precautionary step, but has also expressed "full confidence" in their safety.