Tepco said Monday its trouble-plagued radioactive water treatment system at the Fukushima No. 1 nuclear plant has been partially suspended again.

One of three treatment lines of the multi-nuclide removal facility was halted last week after Tokyo Electric Power Co. found that water passing through it was getting cloudy.

The line was hit by similar trouble in March due to filter gasket corrosion. Tepco later changed the filters and resumed testing it in May.

The company said it doesn't know yet if filters caused the latest problem.

Tepco also said Monday that the Nuclear Regulation Authority approved its plan to build another radioactive water treatment system with higher performance, which is expected to be capable of processing 500 tons of toxic water a day.

The company aims to finish processing around 400,000 tons of toxic water at the Fukushima complex by the end of next March, but whether it can achieve that goal is unclear as the existing facility has faced numerous problems.