Israel ended a stalemate with about 20 African migrants stranded along its border with Egypt for more than a week, allowing two women and a child to enter but turning the rest of the group away.
A statement from Prime Minister Binyamin Netanyahu said on Thursday that although Israel granted entry to two women and a child, the country was "determined to stop the flood" of migrants.
A group of around 20 Eritreans had been stuck outside a nearly-completed border fence, where the Israeli military was providing them with food and water.
Israel allowed the three to enter the country, but sent the rest to Egypt, where officials said they were arrested for allegedly crossing a border illegally.
A government official who asked not to be named said the three were let in on humanitarian grounds. Israeli media said one of the women had been pregnant and had lost her baby.
Rights groups had appealed to Israel's Supreme Court to decide the fate of the group that was stuck at the border, but the agreement to have them return to Egypt was reached before the court made a decision.
About 60,000 African migrants have entered unlawfully in the past few years through the porous Egyptian border and have alarmed Israel, which says they are mostly job-seekers who threaten the demographics in the Jewish state of 7.8 million.
To curb the influx, Israel has been building a fence along the 260km-long frontier with Egypt's Sinai desert and it is due to be completed by the end of 2012.
"We are determined to stop the flow of the infiltrators," Netanyahu said. "We have built a fence to achieve that goal ... and we will continue our efforts to return the infiltrators to their countries of origin."
Humanitarian organisations in Israel said the migrants should be considered for asylum, and many Israelis have been troubled that their country, founded by war refugees and immigrants, should be packing off foreigners en masse.
Most of the African migrants entering Israel are from Sudan and Eritrea.
Under international law, Israel cannot return people to those countries because of their poor human rights records.
Israel's hardened policies have drawn criticism from rights groups who say the country is shirking its international responsibilities and sending migrants back to countries where they could face persecution.
"It's a cynical arrangement that endangers the welfare and security of the migrants,'' said Ran Cohen of Physicians for Human Rights-Israel, which helps migrants.
In a similar standoff last month, Israel permitted four Eritreans stranded by the border to enter after four days.