Recovery workers Monday focused on finding the black box flight recorders from AirAsia Flight 8501, which crashed in the Java Sea off Borneo one week ago. Fransiskus Bambang Soelistyo, head of Indonesia's search and rescue agency Basarnas, said seasonal tropical storms stymied divers' efforts to find the boxes earlier about 103 miles off Borneo, the Antara news agency reported.

Investigators hope the flight data recorder and cockpit recorder will provide answers to why the plane went down. A report Saturday by the Indonesian weather agency said  icing was a possible explanation.

Flight 8501 vanished from radar Dec. 28 on a flight to Singapore from Surabaya, Indonesia. Just before air traffic controllers lost contact, the pilot of the doomed Airbus A320-200 had asked permission to ascend to 38,000 feet to avoid deteriorating weather.

Nine-foot waves, 35 mph winds and poor visibility hampered divers Sunday. Soelistyo said diver safety is of paramount concern.

The Indonesian navy sent two more warships to the search area to help with recovery efforts, bringing to 15 the number of ships Indonesia has committed to the recovery operation, the Jakarta Post reported. Six fixed-wing planes, 14 helicopters and 27 ships in all from Indonesia, Singapore, South Korea, Russia, the United States and Japan are participating in the search effort.

Soelistyo said Sunday five "significant objects" had been located about 90 feet deep, and the recorders should be nearby, the Singapore newspaper the Straits Times reported. He said the search team includes five vessels capable of detecting the black box.

"Our challenge is mud. Lots of mud at the sea bottom," he said.

He admitted however, none of the ships participating in the search has detected any pings, the Independent reported. Air Force Lt. Col. Johnson Supiryadi said it appeared the tail section, where both recorders are stored, appears to have broken away from the fuselage.

Officials have given up hope any survivors among the 162 passengers and crew aboard would be found.

"If God has called your child, allow me to say this: Your child is not to be pitied," the Rev. Philip Mantofa, whose congregation included a quarter of the victims, said during a chapel service, the Associated Press reported. "Your child is already in God's arms. One day, your family will be reunited in heaven."

Meanwhile, Indonesia has opened an investigation into whether airlines have violated terms of their route permits. Jakarta last week said AirAsia did not have permission to fly from Surabaya to Singapore.

Soelistyo said 34 bodies had been recovered as of Sunday. The Post said families have objected to news coverage of the bodies being turned over to them. Indonesia barred journalists from the process in response.