TOKYO >> Japan has raised the maximum radiation dose allowed for nuclear workers, citing the urgent need to prevent a crisis at a tsunami-stricken power plant from worsening.

Despite the increase, surging radiation levels forced emergency workers to temporarily withdraw from the crippled Fukushima Dai-ichi nuclear plant on Wednesday, losing time in their struggle to cool overheating fuel in reactors crippled by last week’s devastating earthquake and tsunami.

The Ministry of Health Labor and Welfare raised the maximum allowable exposure for nuclear workers to 250 millisieverts from 100 millisieverts. It described the move as “unavoidable due to the circumstances.”