JERUSALEM – andnbsp;Israel has quietly repatriated hundreds of Sudanese migrants in recent months, drawing accusations from the United Nations and rights groups that it has coerced the Africans into potentially life-threatening situations and possibly violated international norms for treating refugees.

Israel says the departures have been voluntary, but they follow mass arrests of migrants and vows by Israeli leaders to halt the influx.

Over the past eight years, as many as 60,000 African migrants, most from Sudan and Eritrea, have sneaked across Israel's border with Egypt's lawless Sinai desert, some fleeing repressive regimes and others looking for work and better conditions.

Israel initially tolerated their arrival but has since grown jittery as their numbers swelled, turning some neighborhoods into immigrant slums.

Leaders warn the migrants are a burden and threaten the country's Jewish character.

Over the past year or so, Israel has taken a series of steps to halt the flow. It has built a fence along the border with Egypt that has reduced the number of new arrivals from hundreds each month to just a trickle. Since last summer, it has imprisoned new arrivals, while officials determine whether they meet the criteria for refugee status.

About 2,500 migrants are now believed to be in Israeli detention centers awaiting decisions.

According to advocacy groups that assist the migrants, Israel began shuttling Sudanese migrants out of the country in December. Since Israel has no relations with Sudan, the flights have been routed through third countries, which migrants have identified as Jordan and Egypt.

Sudan is hostile to Israel. It is ruled by Omar al-Bashir, an Islamist who has been indicted by the International Criminal Court on charges of genocide and crimes against humanity for his country's actions in the rebellion in Darfur.

One migrant still in Israel told The Associated Press a friend of his was killed after going home.

"No matter how you look at it, it is an expulsion with almost certainty of death," said Orit Marom, advocacy coordinator for Assaf, a migrant aid organization.

Sabine Hadad, spokeswoman for Israel's Interior Ministry, confirmed that a few hundred migrants have left, and all had done so voluntarily. In some cases, she said Israel provided some financial assistance as an incentive.

"Some asked for money, for help. We did give money," she said. "No one is kicking them out ... (but) you can't prevent them from leaving if they want to."

The presence of the Africans has put Israel in a difficult position. Israel, founded in the wake of the Holocaust, has a long history of providing shelter to Jews who fled persecution, and scenes of haggard migrants reaching Israel initially aroused great sympathy.

Some counter that the persecution of Jews in the Holocaust should not put extra burdens on Israel to look out for the welfare of others.

Israel also is bound by an international treaty that prohibits the expulsion of refugees, but many reject the premise that the Africans qualify.

Israel has long argued that the vast majority of the Africans are economic migrants looking for jobs. Critics say this ignores the dangers Africans face by going home, and that Israel has dragged its feet in evaluating the refugee requests.

Mutasim Ali, a 26-year-old migrant from the war-ravaged Darfur region in Sudan who works at a Tel Aviv hotel, said he knows at least 70 people who have returned to Sudan.

He said he some have told him they were detained at the Khartoum airport, and Sudanese authorities have confiscated other returnees' property and documents. He said his best friend left for Sudan voluntarily, and shortly after, he heard from his friend's brother that he had been killed.

"Many people prefer to die in their own country with dignity than to be humiliated every day in Israel," said Ali.

Sigal Rozen, a migrants' rights activist, said Israel has plastered signs in prisons warning detainees what may befall them.

According to Israel's 2012 law, migrants from Eritrea may remain in prison for up to three years, while the Sudanese could theoretically remain in prison indefinitely because Sudan is an enemy country.

An Israeli plan to build a large detention camp for migrants has been frozen, Rozen said, largely because Israel's border fence has led to a sharp drop in new arrivals.

Some Sudanese migrants, facing lengthy detentions and the threat of arrest, are now choosing to leave.

Migrants have been lining up at a travel agency in Tel Aviv to buy plane tickets home. Some pay for the tickets themselves, while Israel foots the bill for others.

Sharon Harel, assistant protection officer for the U.N. High Commissioner for Refugees in Tel Aviv, said Israel is just now beginning a process of evaluating requests for refugee status, even though the U.N. transferred responsibility for the task to the Israeli government in 2009. Formal refugee status would allow migrants to remain in the country legally.

She said the flights have taken place without coordination, despite frequent U.N. requests to Israel. She said some Africans may have left of their own free will, but those in jail who opted for a departing flight felt pressured to leave.

"If you buy a ticket, have no visa, are desperate in this country ... it's definitely not voluntary return," Harel said.