Tributes have been paid to three British men who were among 176 people who died when a Ukranian Boeing-737 crashed after taking off from Tehran.

They were Mohammad Reza Kadkhoda Zadeh, 40, a British-Iranian who ran a dry cleaning shop in Sussex, Sam Zokaei, a BP employee, and engineer Saeed Tahmabessi.

An investigation was under way after Iranian search and rescue teams found the black boxes from the airliner that crashed on Wednesday soon after takeoff from Tehran’s main airport shortly after 6am local time.

In Britain, BP issued a statement confirming Zokaei as one of the dead. He was listed on a Linkedin page as being a senior reservoir engineer who had studied at Heriot-Watt University in Edinburgh.

The statement added: “We are shocked and deeply saddened by this tragic loss of our friend and colleague and all of our thoughts are with his family and friends.”

Zokaei had worked at BP for more than 14 years, according to the Linkedin profile, and had been based in London following a stint in Cairo.

Kadkhoda Zadeh, known socially as Reza, is believed to have been returning after visiting family in Iran at the end of December and had a daughter under the age of 10.

“He was a lovely guy who was unassuming and loved his job,” said Stephen Edgington, who runs Pet Centre beside the dry cleaners, which Kadkhoda Zadeh operated in the Sussex village of Hassocks.

“When I came in this morning the women who work for him were very upset and we learned that he had been on the flight,” he told the Guardian. “There wasn’t a bad thing about him. He was separated from his wife and had a young daughter who he would sometimes bring in to see the pets.”

A third British-Iranian who was on the flight was identified as Saeed Tahmabessi, a structural engineer who was a PhD student in London and worked for Laing O’Rourke in Dartford, Kent.

A spokesperson for the construction company said: “Everyone here is shocked and saddened by this very tragic news. Saeed was a popular and well-respected engineer and will be missed by many of his colleagues. Our thoughts are with his family and friends at this most difficult time and we will do all we can to support them through it.”

He had been a PhD research student since June 2018 at Imperial College London, according to a Linkedin profile, and since January 2017 had worked as a chartered structural and civil engineer for Laing O’Rourke.

After studying civil engineering at the University of Tehran between 2002 and 2005, he was a student at the University of Greenwich and later at the University of Surrey.

A spokesperson for Imperial College London described him as a brilliant engineer who had a bright future.

“His contributions to systems engineering earned respect from everyone who dealt with him and will benefit society for years to come,” they added.

“He was a warm, humble and generous colleague and close friend to many in our community. Our thoughts and sincere condolences are with Saeed’s family, friends and colleagues, as well as all those affected by this tragedy.”

The plane belonged to Ukraine International Airlines, which said the Boeing 737 involved in the crash had been built in 2016 and was checked only two days before it went down.

Preliminary statements by Iranian and Ukrainian authorities suggest the plane suffered an engine malfunction, though the airline did not detail any reasons for the crash.