A worker at Japan's crisis-hit Fukushima Daiichi nuclear plant died Friday in an accident when he was digging a ditch, the operator Tokyo Electric Power Co.(TEPCO) said. The worker, who is in his 50s, was buried under falling sand and concrete debris near a storage tank for radioactive waste when the accident happened. He was pulled out by co-workers but later confirmed dead at a local hospital, the utility said. TEPCO admitted it was the first time a laborer had died as a direct result of an accident inside the plant since the nuclear disaster in March 2011, the world's worst since Chernobyl in 1986. "I feel very sorry and mourn the loss" of the worker, said TEPCO spokesman Masayuki Ono. The utility will suspend cleanup operations for an immediate safety inspection on Saturday, Japan's Kyodo News reported. TEPCO has been widely criticized for its handling of the cleanup. The operator was plagued by a series of leaks of radioactive water from hastily built tanks at the site last year and it has repeatedly promised to improve working conditions