A greaselike substance has been found splattered on six areas of the A-Bomb Dome in Hiroshima's Peace Memorial Park, local police said Monday.

A passerby had notified police Sunday evening that a substance resembling grease was splattered on a stone plaque placed on the northern side of the dome.

The dome served as the Hiroshima Prefectural Products Exhibition Hall when the bomb razed the city on Aug. 6, 1945.

It has been preserved as a peace memorial and has been designated a World Heritage Site by UNESCO.

Investigators found three smears in the shape of human palms on the plaque and took samples to identify the substance.

Workers used various agents on a trial-and-error basis to remove the substance, the composition of which was not immediately known.

An ensuing investigation showed that three other spots had been similarly vandalized.

This is the first time for the plaque to be defaced, the city said.