Protesters gathered to show Armenian President Sarkisian their views.
Armenians in Lebanon have protested over a proposed agreement between Armenia and Turkey.
As the BBC's Jim Muir reports, they want Turkey to recognise as genocide the killing of some 1.5m Armenians under Ottoman rule during World War I before any deal is signed.
Waving the red, blue and orange Armenian flag, chanting slogans and brandishing banners condemning the proposed agreement with Turkey, thousands of Lebanese Armenians converged on a luxury hotel in the suburbs of East Beirut to leave President Serzh Sarkisian in no doubt about their feelings.
Many came here on foot from the suburb of Burj Hammoud and other nearby areas where Armenian survivors settled after fleeing Turkey 90 years ago.
Those survivors established now-thriving communities in bustling streets where most of the shop signs and advertisements are now in Armenian.
President Sarkisian flew to Lebanon on the latest leg of a mission to the diaspora which had earlier taken him to Paris, New York and Los Angeles.
He is trying to persuade anxious Armenian exiles that peace with Turkey does not mean forgetting what they call a genocide in which 1.5 million perished.
In Lebanon, he will face an uphill task in talks with community leaders.
All the major political parties - which wield considerable influence in the intricate and delicate Lebanese political system - are against the proposed accord with Turkey.
So too are all the religious leaderships.
Lebanon's 150,000 or so Armenians are virtually all descended from survivors.
Most trekked overland through Syria, while a few arrived directly by boat.
Generations may have passed since then, but the Armenian community is tight-knit, memories are long and vivid, and feelings intense even among the young for whom Turkey is a terrible myth.
"I was born and bred here, but I still feel very, very Armenian," said Ani Didanian, who is 44.
"My great-grandfather walked to Lebanon. Two of his aunts froze to death in the snow, an uncle was massacred, and his father and mother were lost - they never found them.
"We're here because we want to say no to the agreement. It is not fair. You can't just negate the past, and go on.
"The Turks should pay the price for all the stolen land, and the one and a half million victims that died."
Fear of forgetting
Mher Krikorian, a 21-year-old student, said that Armenians of the diaspora were worried that the horrors of the past would be glossed over and forgotten.
"Our Armenian history is full of blood, and with this protocol they will forget it. We want our culture, our history to be known around the world.
"And we still have lands over there, inside Turkey. All around the world, we Armenians are one, and we are against this protocol."
This was not just a demonstration by angry young men. There were angry old ladies too.
"My grandfather was one of seven brothers in the same family, but the other six were all hanged and only he escaped," said 70-year-old Sosi Azadourian.
Lucy Srabian said 'moral compensation' was needed
"My grandmother hanged herself, because they were raping all the women."
Lucy Srabian, a 42-year-old journalist, said her grandparents made their way to Lebanon as the only survivors from a family of 60 souls.
"When President Sarkisian says 'We're not going to forget the genocide', what is he going to do not to forget it?" she asked.
"If he is going to have a friendly relationship with Turkey, then where does the genocide stand? We don't know, and that bothers us all."
"It's the moral compensation we need, the recognition. We cannot deal with it if they don't admit they've done something wrong, and we feel that they feel with us.
"Of course there is the issue of compensation, but we have to be realistic. We must see in this world if we can live together. But we don't want to be fooled."
Unlike most of those demonstrating here against the protocol, Rubina Markosian has a foot in both camps.
The Armenian community is tight-knit
One of her parents was born in the diaspora in Lebanon, the other in Armenia itself when it was part of the Soviet Union.
She has just returned to Lebanon with a different perspective after living and working for the past 10 years in Armenia, where almost all the political parties support the agreement.
"They [the diaspora demonstrators] want to stay hostile towards Turkey, because they don't know what their next step would be," she said.
"I personally think Armenians have come to a dead end. We cannot claim our land [in Turkey] back, and we're demanding recognition which I don't know is going to satisfy us in the end.
"But the Armenian diaspora survives on the genocide, and there are a lot of worries about what's going to happen once the genocide is recognised.
"Is the diaspora going to survive? It gives them a cause and an identity, and they will lose both."