(CNN) -- Passengers feeling the bumpy impact of a labor dispute at American Airlines had another concern over the weekend when a row of seats dislodged during a flight and prompted an emergency landing, the airline said on Monday.
A Boeing 757 from Boston to Miami carrying 175 passengers diverted to New York's John F. Kennedy Airport on Saturday when three seats in Row 12 came loose shortly after takeoff.
The plane landed safely and no injuries were reported. Passengers were transferred to a second plane and the flight resumed later in the day.
"We are conducting an internal investigation into why Row 12 was not locked down. There are at least a half-dozen reasons why a row of seats could become loose," Andrea Huguely, an airline spokeswoman, said in a statement.
"We never have -- nor will we -- compromise the safety and reliability of our fleet," she said.
The Allied Pilots Association, the largest independent pilot union and a certified collective bargaining agent for the 10,000 pilots of American Airlines, said the interior overhaul of the plane was performed by third party maintenance workers
"It's an embarrassing problem," said Gregg Overman, a spokesman for the pilots' union.
The airline said standard maintenance practices are followed and the incident was reported to the Federal Aviation Administration.
American Airlines declared bankruptcy last year and has been wrangling with its major unions over contract terms.
In the past month, more than 1,000 American flights have been canceled and 12,000 delayed.
Airline management blames the situation on pilots filing what it claims are frivolous reports about aircraft problems. The union representing American's pilots denies management's assertion.