A man hijacked a small plane in the Central American nation of Belize and stabbed two passengers and a pilot before being shot and killed by one of the stabbed passengers, officials have said.

The Tropic Air plane was travelling from Corozal to the popular tourist destination of San Pedro with 14 passengers and two crew members on board when it was hijacked.

The Cessna Caravan circled in random directions for nearly two hours and was followed by a police helicopter before it touched down at an airport in the coastal town of Ladyville.

Authorities in Belize declared a full emergency when the incident began around 8.30am local time, according to the Belize Airport Concession Company.

"In the face of incomprehensible pressure, our pilot acted with extraordinary courage and calm, guiding the aircraft to a safe landing," said Maximillian Greif, the CEO of the airline company.

"His actions were nothing short of heroic."

The two wounded passengers and pilot were being treated for their injuries at a hospital, officials said.

A US State Department spokesperson described the incident as "horrifying".

The Belize police commissioner, Chester Williams, identified the hijacker as Akinyela Taylor and said he was a US military veteran, but US officials did not confirm that detail.

One of the stabbed passengers was licensed to carry a firearm and shot and killed Taylor, the commissioner said.

He was stabbed in the back and suffered a puncture to his lungs and remains in critical condition.

"We are praying for him," Mr Williams said. "He's our hero."

He said Taylor was demanding to be flown out of the country, possibly to Mexico, and at one point wanted the plane to land to take on more fuel.

A US Embassy spokesperson in Belize said Taylor also insisted he be taken to the US, adding: "We don't know why he wanted to go back to the United States."

US officials said they do not know Taylor's motive for the hijacking but were working with authorities in Belize to discover what happened. (Sky News/AP, but headline rejigged)

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