MOSCOW, JAN. 19 -- A pro-Communist National Salvation Committee declared today that it was taking power in the Soviet republic of Latvia, an announcement that was read without comment on state-run television news.

But the committee, apparently similar to a shadowy, pro-Moscow group that made the same claim last Sunday in the neighboring Baltic republic of Lithuania, showed no sign of implementing its declaration.

"No coup has taken place," said Janis Krumins, an aide to the republic's president, Anatolijs Gorbunovs, who called the claim "disinformation." Ever since Sunday's paratroop attack on the Lithuanian television center in Vilnius that left 13 civilians dead, Latvian government officials have been trying to negotiate with army and Moscow officials to avoid a similar occurrence in their republic.

Alfreds Rubiks, the Latvian Communist Party leader and head of the committee, has been trying for a week to gather popular support, especially among the large Russian-speaking minority in the republic. At one rally this week, he told a crowd of 10,000 that the Latvian parliament had to step down and then said: "I hereby proclaim we have taken power."

The Latvian parliament, which declared the republic's intention last May to secede from the Soviet Union, has set up huge concrete barricades around its building to block a potential military attack. The Lithuanian and Estonian legislatures have taken similar precautions.

Anatoly Denisov, a member of the Soviet legislature investigating events in Latvia, said: "The situation . . . is not that critical. The army is no longer a threat."

Tens of thousands of Latvians marched through the streets of Riga, the capital, this morning in a two-mile-long funeral procession commemorating the death of Roberts Murnieks, a 39-year-old Latvian Transport Ministry driver who was shot dead Wednesday by Soviet internal security troops.

Murnieks was shot in the back of the head as he drove a van across a bridge. The leader of the security force, Capt. Cheslav Mlynik, told the independent news service Postfactum that his men fired in reaction to shots coming from a bus.

On the same day as Murnieks's death, the security troops set fire to cars, forced others to stop and searched drivers and passengers. Latvian officials said the troops also fired on an ambulance carrying a woman and two children.

On Friday, Soviet Foreign Minister Alexander Bessmertnykh "expressed concern" to U.S. Ambassador Jack Matlock that the U.S. media and Congress had portrayed events in Lithuania in a one-sided manner that could aggravate the situation, a ministry spokesman said.