Boeing shares were lower Monday after South Korea announced it is launching an investigation following the deadly Jeju Air crash over the weekend that involved a Boeing jet.

South Korea's transport ministry has extended special inspections of all 101 of the Boeing 737-800 jets run by the country's airlines by a week, after the worst aviation disaster on the country's soil,

South Korean officials are struggling to determine what caused a deadly plane crash that killed nearly 180 people on board, with the nation saddened, shocked and ashamed over the country’s worst aviation disaster in decades.

Accident investigators are trying to find the cause of a Jeju Air fatal crash landing that killed 179 of the 181 on board the flight.

After overcoming pariah status at the end of the last century, South Korea must learn what caused the catastrophe on Dec. 29 and what lessons to draw from it.

South Korea's government said on Monday it will extend the shutdown of Muan International Airport by a week to Jan. 14, citing the ongoing investigation into the crash of a Jeju Air jet that killed 179 passengers on board.

For decades, Boeing has maintained a role as one of the giants of American manufacturing. But the the past year's repeated troubles have been damaging.

Shares of Boeing fell in early trading on Monday, one day after a Boeing model 737-800 was involved in the Jeju Air plane crash in South Korea that killed scores of passengers. The slide came hours after South Korea's transportation ministry announced it would investigate the crash and conduct a full inspection of all Boeing 737-800 aircraft in use in South Korea.

Boeing shares were down as much as 6% Monday morning. Authorities in Korea believe a bird strike could have been a factor in the fatal crash.