Dozens of rescue workers and journalists walking through the swamp at night reached the edge of the crash site but did not immediately find survivors. Reporters said they had found only small, scattered pieces of wreckage before they had to abandon the search because of darkness and deep water. Teams said they would resume at first light and follow the debris trial in hopes of finding the main part of the wreckage.
The chief executive of Kenya Airways said he had no news about the plane's condition or about the 114 people who were on board.
"We have no confirmed information about survivors or any possible casualties," Titus Naikuni told a news conference in the Kenyan capital of Nairobi.
The cause of the crash remained unclear.
The wreckage was found about 12 miles southeast of Douala, along its flight path. It had been difficult to spot because it was hidden by a thick canopy of trees, Naikuni said.
The Nairobi-bound Boeing 737-800 had departed from Douala airport early Saturday, an hour late because of rain, with 105 passengers and nine crew members on board. The plane issued a distress call, but then lost contact with the radio tower between 11 and 13 minutes after takeoff, officials said.
The search for the wreckage initially focused on the thickly forested mountains near the town of Lolodorf, about 90 miles southeast of coastal Douala. But when it was found just 12 miles away, it raised questions about whether the plane had flown some distance and then turned around and headed back to the airport along the same flight path.
Rescue vehicles including ambulances and fire trucks sped to the scene of the crash, sirens blaring. Rescue workers could not drive all the way to the crash site by car, and completed the journey by foot. Journalists with the rescue convoy said it took 40 minutes to walk from the road to the edge of the site.
"We are actively looking for survivors," said Thomas Sobakam, chief of meteorology for the Douala airport.
Heavy rains hampered the search-and-rescue effort in the fog-shrouded forest. At the same time, aviation authorities sent out a ground crew to investigate claims by fishermen living in the swampy mangroves near the Douala airport.
Several reported hearing a loud sound at the time of the suspected crash.