"This shows the authoritarian face of the BJP government," it added.
Yechury and Raja had written to Satya Pal Malik on Thursday informing him of their visit and requesting him to facilitate their entry.
"Both of us had written to the Jammu and Kashmir governor requesting him that there should be no hurdles for our visit... despite that we have been detained. I wanted to meet my ailing colleague and our comrades who are here," Yechury told PTI.
On Thursday, Congress leader Ghulam Nabi Azad was detained and sent back to Delhi from the Srinagar airport.