Radiant in a long white gown and veil, 29-year-old Lebanese bride Israa Seblani stands smiling and posing for her wedding video. The scene is shattered by a deafening roar, and a powerful shockwave that nearly blows her off her feet.

The dramatic footage captured the moment when a massive explosion rocked the Lebanese capital on Tuesday, killing 135 people and injuring more than 5,000.

Seblani, a doctor working in the United States, helped to check on the injured nearby, before fleeing central Beirut's Saifi square to safety.

A day later, she and her husband Ahmad Subeih, 34, a businessman in Beirut, were struggling to process what happened.

"I have been preparing for my big day for two weeks and I was so happy like all other girls, 'I am getting married'. My parents are going to be happy seeing me in a white dress, I will be looking like a princess," she told Reuters.

"What happened during the explosion here – there is no word to explain... I was shocked, I was wondering what happened, am I going to die? How am I going to die?"

Behind her, piles of smashed glass from the blown-out windows of the hotel where she was due to stay littered the ground, along with crushed remnants of flower arrangements that had adorned banquet tables.

Seblani arrived in Beirut three weeks earlier to prepare for her wedding.

Subeih recalled the aftermath of the blast, which officials have blamed on a huge stockpile of highly explosive material stored for years in unsafe conditions at the port.

"We started to walk around and it was extremely sad, it was not describable the devastation and the sound of the explosion," he said. "We are still in shock... I have never heard anything similar to the sound of this explosion."

"I feel so sad about what happened to other people, about what happened to Lebanon," added Seblani. "When I woke up and saw the damage that happened to Beirut, the one thing I said was thank God we are still alive."

After the blast, she and her husband tried to compose themselves and carry on with their celebrations.

"My husband told me to continue, we can't stop. I was like okay, why not, we continue. I was not living the moment actually, I was like walking, my face was smiling, my lips were smiling, that's it, not more. Then we went to have a dinner."

Subeih recalls entering the damaged hotel on Wednesday to retrieve belongings and passports.

"The scene in the room was unbelievable," he said.

He is waiting for a visa to the U.S. so he can join his wife there. Seblani loves Lebanon but feels that after Tuesday's blast, living there is not an option.

She is still trying to find joy in a wedding she took so long to prepare.

"There is a lot of damage, many people were killed and wounded. But also if I want to look at us, myself, my husband, the photographer – how we escaped unharmed, I thank God for protecting us.

"This alone makes me feel optimistic and to keep the joy of the occasion that I came here to celebrate."