Backers of the Soviet dissident group that monitors Kremlin compliance with the Helsinki accord's provisions on human rights met publicly today, the first such meeting since two of the group's leaders were arrested. They hailed President Carter's meeting today with exiled dissident Vladimir Bukovsky.

Valentin Turchin, head of the Moscow chapter of Amnesty International, who himself has been threatened with arrest by police recently, said the White House meeting had "historic" significance as a reaffirmation of Carter's support for human rights and become of Bukovsky's position as a "symbol" of the struggle for those rights.

Today's gathering in a crowded room at the apartment of Yuri Orlov, arrested Feb. 10, was, meant to show that the remaining supporters intend to go on speaking out despite the sharp increase in Soviet pressure against them.

The arrests of Orlov and Alexander Ginzburg had prompted criticism from the Carter administration, but there seems to be no indication that the American remarks have had any influence on the cases thus far.

Two Jewish activists entering the U.S. embassy today accompanied by American counsul Lawrence Napper were seized by police and plain-clothesmen outside the embassy building and held for six hours, one of them said later. American officials confirmed that the Soviets maintained that the Jews - Benjamin Fain and Joseph Begun - were "dangerous criminals".

The embassy sent a protest to the Soviet Foreign Ministry, an embassy spokesman said.

[Dutch Foreign Minister Max van der Stoel. On an official visit to Czechoslovakia, held an unprecedented meeting in Prague with human-rights campaigner Jan Patocka, Reuter reported. It was the first time that a foreign statesman had conferred with a Czechoslovak human-rights activist.]