Screaming "They're going to take us down!" a JetBlue pilot stormed through his plane rambling about a bomb and threats from Iraq on Tuesday until passengers on the Las Vegas-bound flight tackled him to the ground just outside the cockpit, passengers said.

The captain of JetBlue Airways Flight 191 from New York's John F. Kennedy International Airport was taken to a hospital after suffering a "medical situation" on board that forced the co-pilot to take over the plane and land it in Amarillo, Texas, the airline said.

The unidentified pilot seemed disoriented, jittery and constantly sipped water when he first marched through the cabin, then began to rant about threats linked to Iran, Iraq and Afghanistan after crew members tried to calm him down in the back, passengers said.

"They're going to take us down. They're taking us down. They're going to take us down. Say the Lord's prayer. Say the Lord's prayer," the captain screamed, according to passenger Tony Antolino.

Josh Redick, who was sitting near the middle of the plane, said the captain seemed "irate" and was "spouting off about Afghanistan and souls and al-Qaida".

The outburst came weeks after an American Airlines flight attendant was taken off a plane for rambling about the Sept. 11, 2001 terrorist attacks and her fears the plane would crash. An aviation expert remembered only two or three cases in 40 years where a pilot had become mentally incapacitated during a flight.

Gabriel Schonzeit, who was sitting in the third row, said the captain said there could be a bomb on board the flight.

"He started screaming about al-Qaida and possibly a bomb on the plane and Iraq and Iran and about how we were all going down," Schonzeit told the Amarillo Globe-News.

The captain was tackled by several passengers after he tried to re-enter the cockpit, which had been locked by the co-pilot, the Federal Aviation Administration said in a statement.

Antolino, a security executive who said he sat in the 10th row, said he and three others pinned down the captain as he ran for the cockpit door and sat on him for about 20 minutes until the plane landed at Rick Husband Amarillo International Airport at 10 am.

"That's how we landed," he said. "There were four of us on top of him ... Everybody else kind of took a seat and that's how we landed."

An off-duty airline captain who was a passenger on the flight entered the flight deck before landing in Amarillo and took over the duties of the ill captain, the airline said in a statement.

The captain was taken to a local medical facility after the plane landed, the airline said without elaborating.

Shane Helton, 39, said he saw emergency and security personnel coming on and off the plane as it sat on the tarmac in Amarillo. "They pulled one guy out on a stretcher and put him in an ambulance," said Helton, who went to the airport with his fiance to see one of her sons off as he joined the Navy.

Authorities interviewed each of the passengers once they had landed and left the plane, said 22-year-old passenger Grant Heppes.

"I had no idea it was an employee until it really started happening," Heppes said. "I just assumed it was a passenger who flipped out."