Fire departments in major cities nationwide announced Sunday they will launch safety inspections of 6,300 buildings to ensure that a deadly fire like the one in Tokyo that claimed 44 lives Saturday never happens again.

"We will examine some 4,000 buildings in Tokyo to check if these buildings are equipped with fire safety measures and evacuation routes," said Shinji Nonaka, a spokesman for the Tokyo Fire Department. "If we find any deficiencies, we will immediately demand building managers improve fire safety measures," he said.

Meanwhile, about 70 police officers and firefighters searched a building in a popular night spot in Tokyo's Shinjuku Ward for clues as to what caused the early morning fire and explosion -- the nation's worst conflagration in three decades.