Egypt has carried out mass arrests and unlawful deportations of thousands of refugees fleeing the war in Sudan, Amnesty International said in a report on Wednesday.

The rights group said it had documented 12 incidents in which Egyptian authorities returned an estimated total of 800 Sudanese nationals between January and March this year without giving them the chance to claim asylum or challenge deportation decisions.

It also said it had documented in detail the cases of 27 Sudanese refugees arrested between October 2023 and March 2024, 26 of whom were among those collectively expelled. Refugees had been held in cruel and inhuman conditions ahead of their deportation, it added.

The total number of arrests and deportations are unclear as there are no publicly available statistics. The UN refugee agency said thousands were deported late last year, many of them Sudanese.

Egypt's State Information Service did not immediately respond to a request for comment.

Amnesty International said Egypt's National Council for Human Rights denied its findings about a rise in the number of arrests and deportations of Sudanese refugees, asserting in a response to the group that authorities respect international law.

The arrests were part of a campaign starting in September 2023 in which plain clothes police have made random checks on Black people, arresting those not carrying valid identity documents or residence permits, Amnesty International said.

The checks happen frequently in the capital Cairo and its sister city of Giza, where large numbers of Sudanese have settled, as well as in the southern Egyptian city of Aswan, where many Sudanese refugees stop on their way north.

The war that erupted in April last year between the Sudanese army and the paramilitary Rapid Support Forces has created the world's biggest displacement crisis, with over nine-million fleeing inside Sudan or crossing to neighbouring countries.

More than 500 000 people, or about 24% of the total who have left Sudan, have crossed to Egypt, according to the International Organization for Migration.

Less than two months after the war started, Egypt suspended a treaty commitment to visa-free access for Sudanese women, children and men over 49, slowing entries.

Arrivals led to occasional tensions, with some Egyptians blaming Sudanese and other foreigners for pushing up rental prices, and Egyptian TV commentators citing the "burden" of millions of migrants at a time of high inflation and economic pressures.

After Egypt's foreign currency shortage worsened last year many Africans arrested for not having valid papers were held in squalid conditions and asked to pay fees in dollars to avoid deportation, according to lawyers and witnesses.

European states see Egypt as playing an important role in preventing mass migration across the Mediterranean.

In March, Egypt and the European Union announced a strategic partnership underpinned by 7.4-billion euros of funding, an agreement widely seen as driven by European concerns about migration.