Lawmakers from South Korea's ruling Saenuri Party have said the country should weigh building nuclear-powered submarines as Pyongyang makes progress in its atomic weapons program.

North Korea on Wednesday lofted a submarine-launched ballistic missile (SLBM) 500 km toward Japan — a distance analysts said highlighted weapons advances made by the reclusive regime of leader Kim Jong Un.

In a statement posted to Facebook Sunday, a group of 23 lawmakers led by Saenuri Party floor leader Won Yoo-chul blasted the North's missile test and urged a more robust response by Seoul to Pyongyang's saber-rattling.