China\'s police and cultural authorities have jointly issued a circular calling for tightened museum security after three theft and robbery cases occurred earlier this year. According to Chinese news agency Xinhua, the cases include a May theft at the Palace Museum in China\'s capital, in which several exhibited items on loan from a Hong kong-based museum were stolen. \"People who have been lured by the high profits attained through the theft and smuggling of ancient relics tend to set their targets on various museums,\" said a circular jointly released Tuesday by the Ministry of Public Security and the State Administration of Cultural Heritage. The circular said that police and cultural authorities should examine museum security systems and improve training for museum guards. Museums should make emergency response plans and conduct emergency drills every six months to improve their ability to handle thefts, according to the circular. Police and cultural authorities will carry out security checks in museums before the end of this year, suspending the operation of museums with security flaws, according to the circular. Museum thefts are rare in China. Previous thefts related to China\'s cultural relics largely involved the illegal excavation of ancient tombs. In January, three burglars overcame security guards and broke into a museum in the city of Huanggang, located in central China\'s Hubei Province. The thieves took three bronzeware items dating back to the Warring States Period (475 BC - 221 BC). In February, 16 cultural relics were stolen from the municipal museum of the city of Rugao in east China\'s Jiangsu Province.