An Australian ship will deploy a U.S.-made underwater vehicle, Bluefin-21, Monday night local time in the southern Indian Ocean, USA Today reported, citing an official coordinating the search for the missing Malaysia Airlines Flight MH370.

Over the past few days, teams have been using a device that's towed underwater by ships to listen to signals from the plane’s black box but no new signals have been heard since April 8, giving rise to concerns that the batteries of the flight recorder, which typically last about 30 days, may have died. Meanwhile, an oil slick was reportedly detected within the search area and about two liters of the liquid was collected for testing, reports said.

"Ocean Shield will cease searching with the towed pinger locator later today and deploy the autonomous underwater vehicle Bluefin-21 as soon as possible," Angus Houston, a retired Australian air force official in charge of search operations, reportedly said. “We haven't had a single detection in six days so I guess it's time to go underwater.”

Speaking about the oil spill sighting, Houston reportedly said Monday: “I stress the source of the oil is yet to be determined but the oil slick is approximately 5,500 metres downwind... from the vicinity of the detections picked up by the towed pinger locator on Ocean Shield."

A total of 11 military aircraft, one civil aircraft and 15 ships would assist the search Monday, the Joint Agency Coordination Centre said, in a statement, adding that the Australian Maritime Safety Authority has planned a search area of approximately 18,396 square miles, with the center of the search area lying approximately 1,367 miles northwest of Perth.

The Beijing-bound Malaysia Airlines flight, with 239 people on board, mysteriously vanished on March 8 shortly after taking off from Kuala Lumpur, triggering a massive, international search effort involving dozens of countries and agencies.