A week of national mourning has been declared in Poland after the country's President died in a plane crash.
Lech Kaczynski, his wife and some of his senior officials were killed as the aircraft tried to land in thick fog in western Russia.
The crash took place about 11am local time (7am Irish time) in the Smolensk region.
“The Polish presidential plane did not make it to the runway while landing. Tentative findings indicate that it hit the treetops and fell apart,” Smolensk governor Sergei Anufriev said.
The passengers were on their way to a World War 2 commemoration.
Speaking in Warsaw, the Polish Prime Minister Donald Tusk expressed his deep sorrow.
The Taoiseach is among the many political leaders to extend his sympathies to the Polish people after the tragedy.
Brian Cowen has offered his sincere condolences for what he described as a "terrible tragedy".
A Mass will be held by the Polish Community for President Kaczynski in Dublin this afternoon.
There was some confusion over the death toll in today's crash. The head of Russia’s top investigative body, Sergei Markin, said there were 132 people on the Tu-154.
Poland’s Foreign Ministry spokesman, Piotr Paszkowski, said there were 89 people on the passenger list but one person had not shown up.
“We still cannot fully understand the scope of this tragedy and what it means for us in the future. Nothing like this has ever happened in Poland,” Mr Paszkowski said. “We can assume with great certainty that all persons on board have been killed.”
The presidential Tu-154 was at least 20 years old. Polish officials have long discussed replacing the planes that carry the country’s leaders but said they lacked the funds. According to the Aviation Safety Network, there have been 66 crashes involving Tu-154s, including six in the past five years.
The Russian carrier Aeroflot recently withdrew its Tu-154 fleet from service.
The crash is likely to be a setback in Polish-Russian relations, which had been improving of late after being poisoned for decades over the Katyn massacre.
Russia never has formally apologised for the murders of some 22,000 Polish officers, but Prime Minister Vladimir Putin’s decision to attend a memorial ceremony earlier this week in the forest near Katyn was seen as a gesture of goodwill toward reconciliation. Rossiya-24 showed hundreds of people around the Katyn monument, many holding Polish flags, some weeping.
In Warsaw the national flag was lowered to half-staff at the presidential palace, where people gathered to lay flowers and light candles.
Black ribbons appeared in some windows in the Polish capital.
Poland’s president is commander-in-chief of its armed forces but the position’s domestic duties are chiefly symbolic.
Poland, with 38 million people, is by far the largest of the 10 formerly communist countries that have joined the European Union in recent years.
Last year, Poland was the only EU nation to avoid recession and posted economic growth of 1.7 %.
It has become a firm US ally in the region since the fall of communism – a stance that crosses party lines.
The country sent troops to the US-led war in Iraq and recently boosted its contingent in Afghanistan to some 2,600 soldiers.
US Patriot missiles are expected to be deployed in Poland this year. That was a Polish condition for a 2008 deal – backed by both Mr Kaczynski and Mr Tusk – to host long-range missile defence interceptors.
The deal, which was struck by the Bush administration, angered Russia and was later reconfigured under President Barack Obama’s administration.
Under the Obama plan, Poland would host a different type of missile defence interceptors as part of a more mobile system and at a later date, probably not until 2018.
Mr Kaczynski is the first serving Polish leader to die since exiled World War II-era leader General Wladyslaw Sikorski in a plane crash off Gibraltar in 1943.
US State Department spokesman P.J. Crowley said: “This is a horrible tragedy for Poland and we extend to the people of Poland our deepest condolences.”
Neighbouring Germany’s foreign minister, Guido Westerwelle, said he was “shocked and full of sadness” at Mr Kaczynski’s death.
“All the German people are mourning with our Polish neighbours,” Mr Westerwelle said during a visit to South Africa.