BEIJING - China said Wednesday it has deployed more policemen to protect the Republic of Korea's (ROK) embassy and consulates in the country after a claim that the embassy was hit by a projectile.

Earlier, the ROK's embassy in Beijing reported to Chinese authorities that it was hit on Tuesday by an iron bead that it was suspected had been  shot from an air gun.

"The Chinese side attaches great importance to the report," said Chinese Foreign Ministry Spokesman Liu Weimin during a regular press briefing, adding that the Chinese authorities are carrying out an investigation into the case.

An on-the-spot investigation showed that there was a crack in a window of the embassy, but that it was not caused by any sort of gun, Liu said.

In the past few days, some ROK groups and individuals have protested at China's embassy in Seoul after crew members of a Chinese fishing boat reportedly came into conflict with two ROK coast guards Monday, leaving one of the coast guards dead and the other injured.

"The Chinese side has requested that the ROK side take concrete measures to ensure safety and a normal working environment at China's embassy and consulates in the ROK," said the Chinese spokesman.