British citizens living in Lebanon have described the huge explosion in its capital city, with one describing seeing a “glowing red cloud and plume of smoke”.

Claire Malleson, from Dorset, has been working for the American University of Beirut in the city for two years and was jogging around campus at the time of the blast.

It is not yet known how many British nationals are among those caught up in the aftermath, which has killed at least 100 people and injured more than 4,000 others.

Ms Malleson told the PA news agency: “I just felt this enormous explosion — I thought it was somewhere on campus because it felt a lot closer than the three miles away.

“I could see damage to the buildings near me and a glowing red cloud and a plume of smoke.

“I couldn’t really move, I was rooted to the spot.

“My first thought was to go to a phone and call my parents, in case they saw a newsflash. I found my way back to one of the campus apartments.

“Everyone was walking in a daze. As soon as I got near the campus housing buildings, I could see there was panic. Everyone was saying they felt earthquake-like shakings and buildings had been shaking before the explosion.”

Ms Malleson, 45, said she normally runs closer to the seaport but had changed her routine because of lockdown restrictions. She returned to her flat, which was undamaged, although she said the buildings in the area all had shattered windows.

She said: “Today it is quiet. All my friends are OK, some friends of friends were injured by glass.

“We were warned about possible toxic fumes but the university air monitors (live updates) show no problems, but really all we can do is stay in. As soon as there are official ways to help, we’ll do all we can. The blood banks are all calling for urgent donations.”

She said people speculating about the cause of the explosion was “dangerous”.

“I think that what bothers me the most is people outside Lebanon weighing in and deciding it was an act of aggression or an attack,” she said.

“It feels like that could ignite tensions that we really don’t want here. It takes away from the fact that on the ground here in Beirut the destruction is so catastrophic that people just need to find a way to get through the day, and the weeks to come.

“We already had minimal power supplies and people were already struggling to survive with the financial crisis.

“Speculation is so dangerous in this region.”

Richard Gordon-Smith, from Twickenham, said he felt the shockwaves of the blast more than 12 miles away, describing it as like “being slapped in the face”.

The 39-year-old language teacher and counsellor lives in the coastal town of Damour and was working outside at the time of the explosion.

He told PA: “Suddenly I simultaneously heard a very loud noise and felt something hitting me, almost like a slap in the face, a strike in my ear and my eardrums reverberated painfully.

“It was not just a loud bang like a motorcycle might make, it was something much greater. I looked around and saw other neighbours coming out onto their balconies.

“I thought it was the next neighbourhood along, I didn’t think a shockwave could have come all the way from Beirut.”

He said the incident had come at the “worst possible time” for the city, which is suffering from a financial crisis, as well as dealing with the coronavirus health crisis.

Mr Gordon-Smith said: “All of the hospitals have been wrecked. Patients are out on the street instead of being treated inside hospitals.

“This could exacerbate things beyond the tipping point.

“Talking to some of my friends who are Syrian refugees, and they have gone into a state of complete shock because it brought back many flashbacks, especially for the children who are screaming, and crying and can’t sleep.”