Indonesian search teams worked through a night of heavy rain and winds to locate a passenger jet carrying 62 people that is presumed to have crashed just minutes after takeoff on Saturday afternoon, Indonesia’s Transportation Ministry said.

Officials reported finding plane debris in waters northwest of the capital, Jakarta, though it is not yet confirmed to be part of the flight.

Air traffic controllers lost contact with the Sriwijaya Air Boeing 737-500 as it disappeared from radar screens shortly after leaving Jakarta on a 90-minute flight to Pontianak on Indonesia’s Borneo island, said Adita Irawati, a spokesperson for the ministry, the Associated Press reported.

Fifty-six passengers and six crew members were on board, AP reported. Other reports put the figures at 50 passengers and 12 crew members.

Flightradar24, which monitors air traffic, tweeted that the 27-year-old plane “lost more than 10,000 feet of altitude in less than one minute, about 4 minutes after departure from Jakarta.”

Indonesia’s military has confirmed the plane’s coordinates and sent ships to the location, navy official Abdul Rasyid told Reuters.

Maj. Gen Bambang Suryo Aji of Basarnas, Indonesia’s search and rescue agency, said Saturday that they think the plane may have crashed in the Thousand Islands, an archipelago north of Jakarta, CNN reported. Capt. Eko Suryo Hadi Prayitno of Indonesia’s Sea and Coast Guard also told CNN that search and rescue workers had found an emergency exit and evacuation slide belonging to a Boeing aircraft.

Earlier in the day, fisherman in that area alerted local media that they had spotted metal objects appearing to be parts of a plane.

Local fisherman Solihin told BBC’s Indonesian service that he saw a crash, prompting him and his captain to turn their boat around.

“The plane fell like lightning into the sea and exploded in the water,” he said. “It was pretty close to us, the shards of a kind of plywood almost hit my ship.”

Indonesian media also aired footage of distraught friends and families of passengers gathered at the Jakarta and Pontianak airports, weeping and praying.

A Boeing statement said that it was “aware of media reports from Jakarta, and are closely monitoring the situation. We are working to gather more information.”

Sriwijaya Air’s CEO, Jefferson Irwin Jauwena, told reporters that the plane was in good shape prior to flying, CNN reported.

Sriwijaya Air, based out of Jakarta Soekarno-Hatta International Airport, operates Boeing 737-500 and 737-800 aircraft. It flies primarily within Indonesia but also operates flights to Malaysia, East Timor and China, according to Cirium, an aviation data firm.

While planes are critical for moving around Indonesia, a sprawling mass of 13,500 islands, its local airline industry has also faced repeated security concerns amid accusations of lax regulations and maintenance.

In late 2018, a newer version of the well-used Boeing airliner, dubbed the 737 Max, flown by Indonesian airline Lion Air went down, killing all 189 passengers and crew.

All 737 Max jets were grounded worldwide after a crash five months later in Ethiopia blamed on a design flaw in the flight control system. Investigators later determined that a software flaw and other problems had been overlooked or minimized by company engineers. The 737 Max resumed passenger flights in December.

In 2014, an AirAsia Airbus A320 crashed into the sea, killing 162 people, on a flight from Surabaya, Indonesia, to Singapore.

Lori Aratani contributed to this report.