Two children were seriously injured after a tree toppled in a Massachusetts park.

The horrific incident was caught on surveillance footage at Washington Park in Chelsea.

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Panicked parents and witnesses rushed to help the two children after they heard a cracking sound. Two children – 8-year-old Diego Ruiz and 2-year-old David Mancia – were injured by the tree.

Ruiz suffered bruises and needed staples to close a cut on his head. Mancia remains in the hospital, where his sister says doctors are still determining whether or not to operate.

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The park is closed until all trees are inspected and deemed safe.

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Ruiz's mother, Angeliqua, was wondering why there wasn't anyone out making sure the trees were safe.

While crews were working to make sure they were safe Tuesday, there's no word as to why the tree fell in the park Monday.

"The arborists are trying to determine if the remaining trees are OK. What needs to come down and what can stay, and what caused the problem we had," Joe Foti, from the Department of Public Works, said.