New York shooting: Harrowing witness footage shows smoke filling train after gunman shoots 10

Harrowing scenes have emerged from New York on Wednesday morning (NZ time) after a rush-hour subway shooting injured multiple people.

Ten people were shot, five of whom were critically injured, when the gunman opened fire on the train.

Six others were injured in the commotion that followed.

A hunt is now underway for the person responsible, who filled the train up with smoke by setting off a smoke bomb before opening fire during the morning commute.

Footage filmed by a witness on board a train shows smoke filling up the subway car as passengers panic with confusion about what has taken place.

New York City police commissioner Keechant Sewell described the attack as something out of a horror film.

"He… took a canister out of his bag and opened it," she told reporters. "The train, at that time, began to fill with smoke. He then opened fire, striking multiple people in the subway and on the platform."

Sewell said the attack was not being investigated as a terrorist event.

The incident has already again reignited the US gun debate - a compelling political issue where lax laws have led to the highest rate of civilian firearm ownership in the world. Mass shootings have plagued the United States for decades.

New York Governor Kathy Hochul said the city has had enough.

"We say no more; no more mass shootings, no more disrupting lives… We are sick and tired of reading headlines about crime."

US President Joe Biden has been briefed about the shooting.

Reuters / Newshub.