Human Rights Watch and other NGOs says Israel has turned back dozens of African asylum seekers, mostly Eritreans, trying to enter from Egypt.
"Since June, Israeli forces patrolling Israel's newly constructed ... border fence with Egypt's Sinai region have denied entry to dozens of Africans, mostly Eritreans," HRW and Israeli NGOs the Hotline for Migrant Workers and Physicians for Human Rights said in a joint statement.
"Thousands of [Eritrean asylum seekers] flee persecution in their country every year.
"In forcing asylum seekers and refugees to remain in Egypt and in deporting others, Israel is putting them at risk of prolonged detention in Egyptian prisons and police stations where they cannot claim asylum," it added.
They also face "forcible return to Eritrea and serious abuse by traffickers in the Sinai region".
The NGOs implored Israeli to abandon its policy, reminding the Jewish state it signed the 1951 Refugee Convention in Geneva, which requires "all countries to respect the principle of non-refoulement," a principle of international law which prohibits turning over a victim of persecution to his persecutor.
"Not only are there credible reports that Israeli soldiers are blocking asylum seekers at the border, but also that they are using violence to do so," HRW lawyer Gerry Simpson said.
According to the UN refugee agency (UNHCR), more than 80% of Eritreans seeking asylum throughout the world are recognised as refugees, the statement added.
More than 60 000 Africans are estimated to be living in Israel illegally, most of them in run-down neighbourhoods of southern Tel Aviv.
Most are Sudanese and Eritreans who entered from Egypt's Sinai Peninsula.
Rising tensions over the growing number of illegal immigrants exploded in May when a protest in south Tel Aviv turned ugly, with demonstrators smashing African-run shops and property, chanting "Blacks out!"
Israel's construction of a nearly 250km fence running the length of its border with Egypt is due for completion by year end. – Sapa-AFP