As many as 13 activists of the Kerala Students Union (KSU) - the student organisation of the Congress -- were taken into custody here on Monday night when they arrived with black flags to protest against Karnataka Chief Minister B.S. Yediyurappa, who is in the city to pray at Sree Padmanabha Swamy temple.

They were agitating against the Yediyurappa government's decision to implement the Citizenship Amendment Act (CAA).

They also expressed anger over 7-hour detention of Kerala journalists by the Mangalore police last week. The journalists had gathered there to report on autopsy of two people killed in anti-CAA protests.

KSU leader Rahul said that the police were tight lipped about Yediyurappa's time of arrival.

As the temple had been cordoned, we decided to stage protest at the hotel where he was staying, said Rahul. We would wave black flags when he would visit another temple in Kannur, he added.