A married couple, two elementary school students and a pair of young scientists are among at least six Winnipeggers confirmed dead after a passenger jet crashed in Tehran on Wednesday.

Mohammad Mahdi Sadeghi — who went by Mahdi — his wife, Bahareh Hajesfandiari, and their daughter, Anisa Sadeghi, were on Ukraine International Airlines Flight PS752, which crashed around 6:15 a.m. local time in Iran.

Pembina Trails School Division said two of its students, in grades 5 and 6, died in the crash. CBC News has confirmed Anisa, 10, was the Grade 5 student.

Forough Khadem, who graduated from the University of Manitoba in 2016 with a PhD in immunology, was described as a promising scientist by those who knew her.

"Forough was one of my best PhD trainees, an outstanding scientist and above all, an amazing human being," said Jude Uzonna, who teaches immunology and is the associate dean (research) at the U of M's faculty of health sciences.

"I am utterly devastated and trying to grapple with this."

Also among the 176 passengers and crew who died was Amirhossein Ghassemi, a master's student at the U of M, who was on his way back home to Winnipeg after attending a family reunion in Iran.

"I lose a brother," said his friend and fellow student Morteza Tavakoli.

"Everywhere that we went, we were together. He was like a family to me."

Ghassemi was doing his master's in biomedical engineering, according to Tavakoli.

Amirhossein Ghassemi was pursuing a master's degree in biomedical engineering at the University of Manitoba. (Amirhossein Ghassemi/Facebook)

"He was hopeful towards the future, the situation in our country," Tavakoli said. "He was very enthusiastic. He was very helpful to everyone he met."

Moments before Ghassemi boarded the plane, the two were texting and Tavakoli warned his friend to be careful, he said.

"I told him, once you're on board, everything will be over. I was referring to worries," he said, his voice breaking. "But I didn't really know that his life was about to be over."

'Everyone is heartbroken'

Two other confirmed victims of the crash — Pedram Moosavi BaFrooei and Mojgan Daneshmand, a married couple — were U of Manitoba alumni who were living in Edmonton.

University of Alberta professors Pedram Mousavi and Mojgan Daneshmand, along with their daughters, from left, Daria and Dorina, were among those killed in the crash of Flight PS752 near Tehran. (zaghtweet1/Twitter)

CBC News is working on confirming the status of other individuals from Winnipeg who were also said to have been on the flight.

Mojtaba Montazeri, a close friend of the Winnipeg family of three who died in the crash, struggled to talk about them without breaking down in tears.

"It's hard to hold together and speak about that. Everyone is heartbroken now," he said, pausing every few words to swallow his emotion.

The Sadeghis and Hajesfandiari came to Winnipeg in 2016 and quickly became involved in the community, working in the sponsorship department of the Manitoba Interfaith Immigration Council, Montazeri said.

"They were great people, a great family," he said. "They were very kind and careful and … highly educated."

'We will miss her tremendously'

Mahdi Sadeghi and Hajesfandiari were both civil engineers working at construction companies in Winnipeg. Sadeghi was with a firm called Fresh Projects while Hajesfandiari was with Marwest Construction.

"Bahareh was soft-spoken and kind to everyone. Despite her shyness, she quickly built meaningful relationships with many people," said Armin W. Martens, president for the Marwest Group of Companies.

"Every conversation with her was a real conversation. She was immensely capable but the lasting impression will be the joy she brought us all. We will miss her tremendously."

Rescue workers search the scene where a Ukrainian plane crashed in Shahedshahr, southwest of Iran's capital, Tehran, on Wednesday. (Ebrahim Noroozi/The Associated Press)

Pembina Trails superintendent Ted Fransen said the division's student services team, including mental health and social workers, is supporting the school community as it mourns the loss of two students.

Schools in the division lowered their flags to half-mast in honour of those who died.

Flight PS752 was bound for the Ukrainian capital city, Kyiv, when it went down minutes after taking off from Tehran's main airport Wednesday morning.

Among those on board were 63 Canadians, Ukrainian Foreign Affairs Minister Vadym Prystaiko said. The flight was also carrying 82 Iranians, 11 Ukrainians (two passengers and the nine crew members), 10 Swedes, four Afghans, three Germans and three Brits, the foreign minister said.

CBC News has confirmed that at least six of the victims were from Winnipeg. 2:41

The ages of those on the plane ranged from three to 70, according to a passenger list released by the airline.

The crash happened hours after Iran launched a ballistic missile attack on Iraqi bases housing U.S. soldiers, but Iranian officials said they suspected a mechanical issue brought down the 3½-year-old Boeing 737-800 aircraft.

Ukrainian officials initially agreed, but later backed away and declined to offer a cause while the investigation is underway.

'Humanity, we've really lost a gem'

Forough Khadem graduated in 2016 from the University of Manitoba with a PhD in immunology. (Submitted by Amir Shirzadi)

The U of Manitoba's Uzonna said Forough Khadem texted him Tuesday evening to say she was leaving Tehran. That was the last contact he had with her.

She was in Tehran to visit family members who still live there, Uzonna said, and was on the flight as part of her return trip to Winnipeg.

"I can't believe that she's gone," he said. "I can't.

"With her passing, I think, humanity, we've really lost a gem."

Uzonna had been texting Khadem while she visited family in Tehran. This is a screenshot of his last contact with her. (Submitted by Jude Uzonna)

Tehran happens to be where Uzonna and Khadem first met back in 2010, at a conference hosted by the World Health Organization.

"Forough was one of the students that had been taking us around because she speaks perfect English," Uzonna said. "She was very good at communication, she was very affable."

At the end of his trip, Uzonna told Khadem to contact him if she ever wanted to do a PhD. She later took him up on the offer.

"If you walk into a room where Forough is … you would not leave that room without trying to find out, 'Who is this lady?'" Uzonna said.

"She's somebody that would sacrifice her life for other people. Just a nice human being."

The same year Khadem graduated from the U of M, she was featured as a CBC Manitoba Future 40 nominee, which celebrates leaders, builders and change-makers under the age of 40.

She was lauded for her research in developing immunity to a deadly infectious disease (leishmaniasis), having successfully identified a novel drug target for treatment of the disease. Her findings were published in five journals, with one being highlighted on the cover page of a prestigious journal.

Uzonna and Khadem together at her graduation party. She graduated from the U of M with a PhD in immunology in 2016. (Submitted by Jude Uzonna)

Uzonna told CBC News that Khadem even won a competition against PhD students from other universities, and her reward was meeting with a Nobel laureate.

"When Forough came back, she said, 'Boss, if I die today, I have lived my life. I've accomplished a lot,'" he said.

Khadem had been working as the business development specialist in Winnipeg for Mitacs Inc., a Canada-wide not-for-profit organization, and essentially tried to make links between industries and researchers, to help bring in more money for research.

"We are deeply saddened to hear that Forough Khadem was on Flight PS752 today. We extend our deepest condolences to Forough's family and friends," said Eric Bosco, chief business development officer for Mitacs.

She will be missed dearly! Our humanity lost a beautiful soul ... Rest in Peace my dearest friend and sister! My deepest condolences to the families and friends of all the victims of this tragic plane crash. May God grant us strength as we all go through this difficult time —@HanaVakili

"We will remember Forough's passion for Mitacs, enthusiasm for innovation in Manitoba, and her positive outlook on life. We will miss her humour, her kindness and her warm spirit."

Khadem was involved in other parts of the community other than research, Uzonna noted.

She was a muslim, and she became a Winnipeg Blue Bombers fan because she was entranced by football when she was a newcomer.

Ultimately, Uzonna just wants to know how Flight PS752 went down so soon after takeoff.

In a tweet Wednesday, the U of M extended condolences to Khadem's family and friends.

"We are grieving this devastating loss alongside the many affected by this horrible tragedy," the tweet read.

Mourners came together at the U of M Wednesday afternoon for a vigil in honour of Iranian plane crash victims, some of whom were connected to the university. (Jaison Empson/CBC)

A vigil was held at the U of M at 1:30 p.m. CT Wednesday in recognition of the crash victims, hosted by the university's Iranian Students Association.

Before sunrise Wednesday, the Winnipeg sign at The Forks was dimmed as news of the crash began to come in.

The Manitoba government has also lowered the provincial flag to half-mast in Winnipeg's Memorial Park.