Three dissident activists were seized yesterday by the secret police in what may be the start of a crackdown on the dissident community, Washington Post correspondent Kevin Klose reported.

Agents seized longtime activist Tatyana Velikanova, dissident Russian Orthodox priest Gleb Yakunin and Lithuanian nationalist Anatanas Terleskas, dissident sources said.

These were the first apprehensions of dissidents since the trials last year of Anatoly Scharansky, Yuri Orlov and Alexander Ginsburg.

Velikanova, 47, a mathematician, was a founding member in the 1960s of one of the first major activist groups here, the Action Group for the Defense of Civil Rights. She is a principal figure in the Chronicle of Human Events, an underground publication covering human rights, activities and repressions. Her son-in-law, Vladimir Keidan, said she had been formally arrested, but the charge was not disclosed.

Yakunin, 45, was taken by police yesterday morning during a search of his apartment, ostensibly to testify as a witness in another case, his wife reported. But he had not been released by late last night and authorities instructed his wife to bring warm clothes to him at the KGB's Lefortovo prison, she said.

Dissidents here said Terleskas, 50, a Baltic economist, was arrested in the Lithuanian capital of Vilnius and apparently formally charged.

The three figures seized, not so well known as other major Soviet dissidents of the 1970s, are part of the still-active group of workers in the diverse movement of Russians, Jews, Christian believers and ethnic minority members. Beginning in 1977, the government has moved to suppress the nation's public dissenters by arrest, trial, intimidation and expulsion.