"Some blasts are occurring in Mazza Abou-Kaab, in the area where our Hamas brothers are. We hope that there will be no dead and injured. No exact data are available yet. Until precise data are revealed, we will not make any announcements," the Fatah source told Sputnik.
Earlier, the Lebanese broadcaster Al Jadeed reported the explosion had taken place inside a weapons depot believed to be operated by Hamas.
Rescue personnel were reported responding to the scene, and residents from nearby neighborhoods were being evacuated. Officials have not yet offered any information about potential casualties.
Video posted on social media late Friday night showed a series of explosions and a raging fire.
Regular smaller explosions can be heard in the videos in addition to the massive explosion, suggesting the blaze is setting off individual munitions as it rages.
Sky News Arabia reported that the fire began in a nearby mosque and spread to the warehouse.
According to the UN's Palestinian relief agency, UNRWA, the Burj al-Shemali refugee camp is home to nearly 25,000 Palestinian refugees and was founded in the immediate aftermath of the 1948 Israeli War of Independence, during which nearly 700,000 Palestinians were exiled from the country and denied the right to return after hostilities ceased.
Another, far more massive explosion destroyed much of the Lebanese capital of Beirut on August 4, 2020, when a large amount of ammonium nitrate that was improperly stored at the port went off. The explosion killed at least 218 people, injured another 7,000, and left 300,000 people homeless. It caused $15 billion in damage.