Authorities expanded their investigation of those on board a missing Malaysia Airlines [MAS] jetliner by paying visits to the homes of the flight crew while confirming that the search area had now expanded across 11 countries, Malaysia’s Minister of Defence Hishammuddin Hussein said Sunday during a press briefing.

“The search area has been significantly expanded and the nature of the search has changed. From focusing on mainly on shallow seas, we are now looking at large tracts of land crossing 11 countries,” he said adding the Malaysian-led effort “Has now become even more difficult.”

Hussein said the investigation was now refocusing on the crew and passengers on board the Boeing 777-200ER as well as ground staff who handled the plane before it departed Malaysia. Police interviewed family members of the pilot at his home on Sunday and visited the home of the co-pilot.

Now in its tenth day, the search and rescue operation now involves 25 countries searching two corridors [north and south] with over 40 ships and 58 aircraft now involved, Malaysian Prime Minister Najib Razak said Saturday.

Flight MH370 went missing in the early morning hours of March 8 after takeoff from the Malaysian capital Kuala Lumpur [KL] to Beijing, China. The plane had 227 passengers and 12 crew members on board when ATC lost contact at about 2:40 a.m. local time while it flew over the South China Sea, two hours after it departed Malaysia.

Despite growing search and rescue operations, no wreckage has been located.