Allahabad, July 17: A dozen Congress workers, including the state Youth Congress vice-president Parvez Akhtar Ansari, were taken into preventive custody ahead of Uttar Pradesh chief minister's visit to inspect development work at an Ambedkar village in this district, police said. Ansari and district Youth Congress leader Abdul Rab were among the party workers arrested by police from various places in Khuldabad, the sources said here. Police said the Congress workers were allegedly planning to demonstrate with black flags during Mayawati's visit to Umari village under Bara assembly constituency this afternoon to inspect development works under Ambedkar village development programme. Bureau Report