Poles pay tribute to dead president

• Mourners carry flags and standards at the memorial service, which featured an altar piece bearing photographs of those killed. Photograph: Getty Images

Up to 100,000 mourners, many clutching red and white national flags threaded with black ribbons, packed into the vast Pilsudski Square in central Warsaw to commemorate the victims of the country's most devastating accident since the Second World War.

"They all had their dreams and hopes for the future of their homeland. This is a serious test for us to understand those hopes well and take them into the future," prime minister Donald Tusk, who had been a political rival of Kaczynski, told the crowd. "This is the most we can do for them. We are here to remember them. Poland is here to remember them. We will not forget."

Behind him on the podium a tall white cross rose up between two large black panels bearing the portraits of all the dead, whose names an actor read out one by one.

Kaczynski's twin brother Jaroslaw, a former prime minister who now heads Poland's main opposition party, sat at the front of the mourners with other family members, including the president's daughter Marta, 29. Kaczynski had two grandchildren.

Yesterday's commemoration, which included a three-gun salute and a requiem mass, came on the eve of the planned burial of Kaczynski and his wife in the crypt of Wawel Cathedral in the ancient capital of Krakow in southern Poland.

Among the mourners was Teresa Winkler, 76, who came to honour a president "who took care of the people forgotten by society", such as ageing Second World War soldiers and forgotten Solidarity activists.

"He was a real patriot and a real Pole," Winkler said. "I am afraid it will be hard to find another president like Kaczynski."

Nearby was a group of Chechen refugees who said they were there to honour the first lady for her charity work and efforts to help them.

Members of Solidarity, the freedom movement that Kaczynski supported and that still exists as a labour union, waved their banners.

Many Poles set aside political differences last week after the disaster. Kaczynski's rightist Law and Justice Party was widely expected to lose presidential elections scheduled for this autumn.

"What happened was a great shock for us. We are here today though we didn't like many of the things that those who died represented," said Maciej Gajewski, a 40-year-old engineer who was there with his wife and three children.

"But we are sorry for them. I feel like a Pole here, I feel united with my compatriots in this difficult situation."

A devout Catholic and passionate nationalist, Kaczynski had fallen out with many of his former Solidarity colleagues and been accused of homophobia. Some in his party held extreme views, such as making Jesus the nominal "king" of Poland and warning that Barack Obama's election was a blow to "white civilisation".

Obama himself remains scheduled to attend the Wawel funeral today. But a huge volcanic ash cloud drifting across Europe from Iceland has closed Polish airports and it was unclear how many would manage to come.

So far delegations from Egypt, Macedonia, India, Japan, South Korea, Mexico, New Zealand and Pakistan have called off. Poland's meteorology institute said the ash cloud still covered the entire country yesterday but would partly disperse by early today. Around 100 dignitaries are still expected, however. Some European leaders are heading for Poland by car or train. France's Nicolas Sarkozy said he hoped to fly today.

Russian president Dmitri Medvedev is also set to make the journey to Krakow for the funeral. Many commentators have suggested that Russians and Poles have become closer as a result of the tragedy, despite its poignant location.

Kaczynski and his entourage had been heading last Saturday to the Katyn forest near Smolensk in western Russia to commemorate the 70th anniversary of the massacre of 22,000 Polish officers and intellectuals by the Soviet secret police.

The crash has stunned Poland, not least because of where it happened. Katyn, regarded as dictator Joseph Stalin's worst crime, is a byword for hell for many Poles.

Tens of thousands lined the streets of Warsaw for the return of the coffins from Russia. The area in front of Kaczynski's palace in Warsaw's picturesque Old Town has been transformed into a shrine to the dead, bedecked with candles, flowers, crucifixes and national flags.

Poland's acting president, Bronislaw Komorowski, yesterday said the tragedy had united Poles of all political beliefs and he also thanked Russia's leaders for their close co-operation immediately after the crash and for their gestures of solidarity.

Poland has long had a difficult relationship with Russia, its communist-era overlord, but Poles hope their second Katyn tragedy may bolster a cautious rapprochement begun by Tusk and his Russian counterpart Vladimir Putin.

Last Sunday, in an abrupt change of tack that had been planned before the crash, Moscow allowed for the first time a leading state channel to air Polish director Andrzej Wajda's harrowing film Katyn, which chronicles the 1940 massacre.

For decades until 1990, the Soviet Union and its client government in Poland had denied Soviet responsibility for the murders, blaming Nazi Germany instead.

"It has become known in Russia that (Kaczynski's entourage] were headed to Katyn on a pilgrimage of truth, in defence of a truth, the voicing of which had been punishable by oppression and jail," Komorowski said. "That truth has now triumphed,"

Investigators in Poland and Russia are said to be blaming human error for last Saturday's crash.

Kaczynski's pilot ignored warnings not to land at a fog-bound, decommissioned military airfield near Smolensk and to divert to a major airport, which would have delayed the Katyn observances.

Authorities, however, have decided not to release cockpit conversations from the plane's black boxes until after today's funeral.