Thiruvananthapuram: Revelations by Swapna Suresh, a key accused in a gold-smuggling case, against Kerala Chief Minister Pinarayi Vijayan and his family members and subsequent protests by the opposition seeking his resignation escalated further on Monday after two Youth Congress workers raised slogans against the Chief Minister aboard an aircraft in which he travelled to Thiruvananthapuram from Kannur, an act which CPI(M) termed as "terror activity".