All 170 aboard crashed Ukrainian Boeing 737 jet dead, Iran confirms

"Obviously it is impossible that passengers" on flight PS-752 "are alive," the head of Red Crescent told semi-official news agency ISNA, adding that 170 passengers and crew had boarded the plane.

The Boeing 737 had left Tehran's international airport bound for Kiev before crashing, according to the semi-official Iranian agency ISNA, adding that 10 ambulances were sent to the crash site. 

The plane crashed at 6:22 a.m. local time, and a video circulating online showed the moment of impact.

Boeing has faced a crisis this year.

A ban on the Boeing 737 MAX aircraft became worldwide in March after US President Donald Trump joined Canada and other countries, including Egypt and Lebanon and Gulf countries, in grounding the aircraft amid intense pressure about the safety concerns.

Demands grew for urgent answers over the safety of the Boeing 737 MAX 8 as Ethiopian and US authorities searched for the cause of a deadly crash near the capital of the African nation, which followed a fatal accident in Indonesia in October.

"We're going to be issuing an emergency order of prohibition to ground all flights of the 737 MAX 8 and the 737 MAX 9 planes," Trump told reporters at the White House.

"The safety of the American people and all peoples is our paramount concern."

The Federal Aviation Administration said the decision was based on new evidence gathered at the crash site near Addis Ababa as well as "newly refined satellite data."

The company continues its efforts "to understand the cause of the accidents in partnership with the investigators, deploy safety enhancements and help ensure this does not happen again," Muilenburg said in a statement.

Preliminary accounts of the Ethiopian Airlines flight appear similar to the Lion Air crash in October, which were echoed in concerns registered by US pilots on how the MAX 8 behaves.

Wednesday's crash in Tehran came amid heightened tensions between the United States and Iran that was triggered after the killing of top Iranian General Qasem Soleimani.

The crash was reported just hours after Iran launched retaliatory strikes against US troops housed in Iraqi military bases in the neighbouring country.

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