Reporter's Notebook: A walkie-talkie exploded at a funeral in Lebanon. Chaos ensued.

BEIRUT -- An ABC News team, with correspondent Marcus Moore, was about 20 feet from a blast that went off Wednesday in Beirut. He described the chaos surrounding the explosion, which came one day after thousands were injured when pagers suddenly exploded in people's hands.

As grieving family members, including mothers and children, gathered for the funeral of four of their own killed in Tuesday's pager explosions, another powerful blast pierced the air in southern Beirut's Dahieh district -- a Hezbollah stronghold.

We witnessed the shock and chaos that followed: screaming, desperate cries, and the fear and panic.

A man, screaming, was left with severe hand injuries from the blast -- his hands basically gone. He collapsed to the ground.

The ground was charred at the spot where the man had been standing. Amid the chaos, we saw another man, perhaps a security guard, with a handgun rushing toward the injured. It was pure pandemonium.

People scattered, as did we. No one at the scene knew what was going on.

We were unaware at the time the horror we were witnessing on Wednesday was part of another round of simultaneous blasts across Beirut.

The video filmed by ABC News shows one of a number of more simultaneous explosions across Lebanon on Wednesday.

At least 20 more people were killed and 450 others were injured in the new blasts Wednesday, according to the Lebanese Ministry of Health.

Twelve others -- including an 8-year-old girl and an 11-year-old boy -- were killed and at least 2,800 people were injured in pager explosions on Tuesday. Those injured Tuesday mostly suffered eye and facial injuries while others had injuries to hands and fingers.

Israel was behind the pager explosions across Lebanon on Tuesday, sources confirmed to ABC News.

Hezbollah has vowed revenge for the attack, with the group saying, "This is another reckoning that will come, God willing."