MOSCOW — On the bridge where Boris Nemtsov died in a hail of bullets on Friday night, three rows of lights, in the white, blue and red of the Russian flag, hung between the streetlamps on the bridge and reflected in muddy puddles. The Sunday demonstration that the opposition leader was going to head had turned instead into a procession in his memory, and at the spot on the sidewalk where he died, still heaped with flowers, the crowd chanted, "We won't forget. We won't forgive!"

One block from the Kremlin, the march paused under a drizzly sky, with 20,000 to 30,000 people participating according to some estimates, a far smaller crowd than the record numbers of protesters who took to the streets in December 2011 to protest widespread fraud in parliamentary elections and Vladimir Putin's grip on power.

Sunday's rally also lacked the politically powerful mix of liberal intellectuals and working-class people from those 2011 protests. Yet it was a substantial turnout of both moderate and liberal Muscovites, one of the biggest in recent years.

Walking with her 5-year-old daughter and elderly neighbors, a woman who gave her name only as Tatyana -- many people interviewed withheld their last names, as Russians often do with reporters -- was hard-pressed to name the next steps for the country after the opposition leader's so far unsolved killing.

"Who knows?" she said, raising her eyebrows. "There is very little hope," added her neighbor, a 76-year-old woman.

They said they had come to the march for a simple reason: To voice their liberal views, and protest "the murder of one of ours." The fact neither they nor the march's leaders had a plan for countering the corruption endemic in Russian politics, as many participants admitted in interviews, didn't deter them from showing up.

Hundreds of people carried giant Russian flags, dressing a sea of black winter hats with white, blue and red stripes. Volunteers gave out the flags at the start of the march in a tactic to counter the opposition's image on state-controlled television as unpatriotic and un-Russian.

Though there were chants of "Russia without Putin!" and other liberal slogans from the 2011 movement, marchers generally talked calmly with friends -- or not at all -- along the route. From the sidewalk, it had the quiet of a funeral procession.

Opposition leaders in the front rows of the march included Putin's former Prime Minister Mikhail Kasyanov, young activist Ilya Yashin, ousted parliament member Gennady Gudkov and his son Dmitry Gudkov, who serves in parliament as one of few dissenting voices.

Many protesters had planned to attend Sunday's march even before Nemtsov's death, to express anger at a monolithic political system and unease at Putin's aggressive foreign policy and intervention in Ukraine, according to interviews. But others said they were spurred by Nemtsov's killing.

Anna, 50, said she was attending her first protest ever. When the university instructor heard of Nemtsov's slaying, she thought it was so outrageous, it had to be fake: "I decided it was 'news' like a woman growing a third breast," she laughed.

Yet the killing was a "logical" progression of Russia's political climate, she said, and ordered by a person or persons who "sit in the Kremlin."

From now on, "they will tighten the screws," cutting back on freedom of speech as Russia loses more Russian soldiers in eastern Ukraine, Anna said. Journalists have documented the presence of Russian commanders and tanks in Ukraine, charges the Kremlin denies.

Vladimir Karpin, 26, a university graduate working in a photo and video shop, said there is a lot of hate spouted on state television. Putin has called his opponents a "fifth column," a reference to saboteurs and traitors, Karpin noted. The president "is responsible for this" atmosphere, he said.

Many in the crowd were well-educated, like Tatyana, a 49-year-old photographer, and her geologist neighbor. Sporting a red hat with snowflakes, Tatyana said they "practically don't have any friends who support Putin" though some support the Russian annexation of Crimea and fighting in Ukraine.

There wasn't an authoritative count of Sunday's participants, but there might have been as many as 30,000 judging by how they filled long boulevards near Red Square. At the start of the route, where there were more than 30 metal detectors, even the first surge of people had a 15-minute wait.

It was a big enough group, winding its way past the Kremlin and over the bridge where Nemtsov was killed, to suggest that his murder touched Muscovites. But Putin would not have been there to see it; the president lives in a government mansion outside the capital.

The marchers clearly expected a peaceful event, some of them bringing children and many of them carrying bouquets of flowers. An older woman waiting at the beginning of the route held 10 white, unopened tulips. In Russia, an even number of flowers is for mourning.

An earlier version of this story misidentified Vladimir Karpin as Vladimir Karlin because of a typographical error.