More than a quarter of a million Poles attended an open-air requiem mass for the Rev. Jerzy Popieluszko today as Roman Catholic officials and opposition figures praised the slain cleric as a "national hero" for his dedication to Poland's Solidarity movement.

Thunderous applause broke out as Solidarity leader Lech Walesa proclaimed over the priest's pine coffin: "Solidarity lives because you sacrificed your life for it."

Poland's primate, Cardinal Jozef Glemp, presided at the funeral and appealed again for national reconciliation.

"Let Poles of different social circles meet, not crying over the coffin of a priest, but around a table for dialogue to release initiatives and peace," the church leader declared. "The church has wanted this for a long time and called for it."

A pro-Solidarity demonstration formed after the service as a column of people flowed peacefully to the city center from the white stone church in Warsaw's northern district of Zoliborz, where Popieluszko had ministered. More than 10,000 streamed past the capital's militia headquarters at Mostowski Palace -- the first time protesters had been permitted outside that forbidding, three-story, gray stone structure -- chanting "We forgive," "Come with us" and "Greetings from the underground."

Although water cannons and blue militia vans flanked the procession, police did little to interfere. The crowd dispersed in the downtown area.

With several secret police officers facing charges in connection with Popieluszko's death and social tensions running high, authorities appeared determined to avoid a confrontation today.

Popieluszko's abduction and killing two weeks ago in northwest Poland, as he was returning from a mass in that region, has precipitated a shake-up in the state security service and thrown the government of Gen. Wojciech Jaruzelski into an internal crisis.

The government said last night that two colonels in the Internal Affairs Ministry had been arrested in connection with the case and a brigadier general at the ministry suspended. Three lower ranking secret police officers already have been accused of carrying out the kidnaping and are expected also to be charged in connection with the killing.

The slaying has bound the church and the political opposition in grief. It also has reinvigorated political activists, now calling for the formation of independent committees to monitor civil rights abuses, and it has given the church a contemporary martyr.

In response to a plea by parishioners and Solidarity supporters that Popieluszko be interred on the grounds of his St. Stanislaw Kostka Church, the 37-year-old cleric was laid to rest in a corner of the churchyard. His interment there effectively makes permanent St. Stanislaw's status as a kind of opposition sanctuary. The church gained national prominence through monthly pro-Solidarity "masses for the fatherland" initiated by Popieluszko in 1981.

The Rev. Teofil Bogucki, the pastor under whom Popieluszko served, said at the end of today's mass that many priests had volunteered to carry on Popieluszko's tradition and asserted that the monthly masses would continue.

Glemp conducted the service from a balcony of the church. Below in a forecourt stood the coffin, resting on a high, white bier. A wide swath of silk in red and white, Poland's national colors, ran from the coffin up the length of the church facade.

Loudspeakers broadcast the mass to a throng that filled the square outside the churchyard's flower-covered fences and packed side streets for a radius of about half a mile.

Red-and-white Solidarity banners fluttered above the crowd, naming regions near and far from which their bearers hailed -- among them, the Baltic port of Gdansk, the coal fields of Katowice and the industrial center of Wroclaw.

Some mourners perched on roofs and balconies of houses around the church, or hung in surrounding trees, straining to catch a glimpse of the proceedings, held under cloudless skies in the autumn chill. Church sources said the turnout was the largest since the 1981 funeral of Glemp's predecessor, Cardinal Stefan Wyszynski.

Friends from various walks of life paid homage to the soft-spoken priest in brief speeches. The vice rector of a seminary called Popieluszko "a national hero," a line echoed by Andrzej Szczepkowski, former president of the Polish actors' union, and by Bogucki.

A representative from the Warsaw steelworks, where Popieluszko first got involved with Solidarity during the movement's rise in 1980, said the cleric's "Solidarity boat of hearts" is "still afloat." Speaking for the medical profession, a doctor voiced the hope that Popieluszko's sacrifice would "bear the fruit of good for the nation."

Representing the government was Deputy Premier Zenon Komender, a member of the progovernment Catholic lay party Pax. He did not speak.

Walesa captured best the day's mood in his remarks conveying solemnity and a firm determination to carry on the peaceful struggle for civil rights in Poland.

"Over the coffin of our brother we swear that we will never forget this death," the Nobel Prize-winning union leader said, facing the largest audience he has been allowed to address openly since the crushing of the independent Solidarity trade union in December 1981. The crowd interrupted him, shouting back: "We swear, we swear."

"We will always remember Father Jerzy and his teachings," Walesa continued. "He was a good and brave man, a great chaplain, priest and the herald of the national cause through all his life.

"We say farewell to you, God's servant, swearing that we will never give in to violence, that we will be in Solidarity in the service for the homeland, that we will respond with truth to lies and with goodness to evil."