At Santo Domingo Sisters beauty salon in Flatbush, the hairdressers and the ladies whose hair they straighten are from the same island, but they don’t speak the same language. The stylists are Dominican; the clients, for the most part, are Haitian.

While common in this part of Brooklyn, it’s a dynamic that is foreign to her native Dominican Republic, one of the stylists, Divina Amarante, said as she misted a Haitian customer’s newly styled hair.

“Haitians are really discriminated against there,” Ms. Amarante, 48, said in Spanish.

Even so, the stylist said that reports last month of a rapid mass expulsion of at least 3,500 Haitian immigrants from the northeast of the Dominican Republic surprised and dismayed her and her colleagues.

The deportation was set off when a Dominican businesswoman was killed, aid workers have told reporters. The assassins allegedly were Haitian, and that unleashed a furious response in a remote section of the impoverished country. Deluged with refugees and migrant workers from its war-torn neighbor, the Dominican government appears to have supported the rapid – and reportedly violent – deportations. The action, also said to have included Haitians who were born in the Dominican Republic, prompted a formal protest from the U.N. high commissioner for refugees May 17.

While the president of the Dominican Republic, Leonel Fernandez, has maintained that enforcement of immigration controls is his nation’s sovereign right, Haitian and Dominican immigrants in New York are uniting to demand accountability.

“It goes without saying that in the city of New York, if a Dominican commits a crime, we do not allow this to become a generalization applied to the rest of the Dominican community,” a a coalition of community leaders said in a letter to Mr. Fernandez. The letter, presented at a small protest at the Dominican Consulate last month, continues: “Sadly, the evil monster of anti-Haitian sentiment that proliferates throughout the entire Dominican society was reawakened.”

The roots of animosity against Haitians go back nearly a century to when they were first brought to the Dominican Republic to work the sugar plantations, a founding member of the Haiti Support Network in New York, Raymond Laforest, said. Apparently unhappy with the growing Haitian community, in the fall of 1937 the notorious Dominican dictator, Rafael Trujillo, ordered soldiers and police to massacre 15,000 to 20,000 Haitians. Mass deportations, too, are not new: In 1991 and 1997, tens of thousands of Haitians and Dominicans of Haitian descent were expelled in purges that drew international criticism.

Mr. Laforest, who also is a union organizer, is a coordinator of a vigil scheduled for this afternoon in front of the United Nations to demand a stop to discrimination and deportations. Backed by a coalition of a dozen Haitian and Dominican groups, Mr. Laforest said he expects the demonstration to draw hundreds.

The 2000 Census counted 369,186 Dominicans in New York, making them the city’s largest immigrant group, and 95,580 Haitians. On the island, the two countries each have populations about equivalent to that of New York City, around 8 million.

While geographic neighbors, Haiti, a former French colony, has a predominantly black population, while most of the population of the Dominican Republic, formerly a Spanish colony, is white and mixed-heritage.

Despite the long history of conflict between the neighboring countries, Mr. Laforest said tensions are mitigated in New York by their shared experience as two of the city’s largest immigrant communities.

“What we found out is there are many decent Dominican people who understand our struggle,” Mr. Laforest said. “Over here both Haitians and Dominicans suffer prejudice and as immigrants fight for common rights.”

Indeed, more Dominican groups than Haitian groups are planning to protest today. The director of the Northern Manhattan Coalition for Immigrant Rights, Raquel Batista, said many members of New York’s Dominican community are particularly empathetic to the current situation because of their firsthand experiences with deportation.

On the island, however, she said tensions run high, intensified by a deteriorating economy.

“There’s more unemployment, and it breeds more fear of instability, and things like this happen,” Ms. Batista said. It is up to President Fernandez, she said, to show that blaming the Haitian community is wrong.

“We really are looking to see some sort of leadership from the president, and he hasn’t shown any around this,” she said.

So far, the letter sent from the coalition to the Dominican president has had no visible response. A spokesman for the consulate in New York, Nelson Encarnacion, said yesterday that a meeting of the administration’s immigration council would take place in July to assess the policy. In the meantime, however, he maintained that his government’s action was no different from the deportation of law-breaking immigrants from America.

In comparison with the estimated million Haitians who flooded the border, he said, this was a drop in the bucket – and in a few days the expelled Haitians would cross back into the Dominican Republic.

“Every day the United States deports people – Dominicans, Mexicans – and nobody protests because it’s a right the United States has,” he said in Spanish.