Israel has begun moving African asylum seekers into a new detention facility in the country's southern desert, in a move that has been harshly criticised by human rights groups.

The Israeli prison service said 480 African asylum seekers, who had been held in Shaharonim detention centre, were transferred to the new facility on Thursday, and about 1,000 asylum seekers would be held there by the end of the month.

An amendment to Israel's "Anti-Infiltration Law" was passed by parliament, the Knesset, on Tuesday, and shortened the mandatory prison terms for African asylum seekers who have illegally entered Israel from three years to one year.

The Israeli government said the law "creates a suitable balance between the right of the State of Israel to defend its borders and prevent infiltration, and its obligation to act in a humanitarian manner toward anyone within its borders and protect the human rights due to every person".

But the asylum seekers will now be held in the new detention centre, known as Sadot, indefinitely without charge or trial until they can be sent back to their home countries.

The detention of African asylum seekers, a group of Israeli human rights groups said in a statement on Tuesday, "is not only draconian, undemocratic, and a fatal blow to human rights, it will also do nothing to help the already marginalized residents of South Tel Aviv", an area where many asylum seekers live.

In the new facility, asylum seekers will be locked down at night, and forced to check-in with the Israeli authorities three times per day. They will also be barred from working outside the centre.

Human rights groups have called the new facility a de facto prison, a charge that Israel denies.

Speaking to Al Jazeera in November, before the law was officially approved, Marc Grey, spokesperson for the Association for Civil Rights in Israel (ACRI) said: "We don’t see this as an improvement... The law itself, whether it’s three years or one year [of detention]… it’s still just absolutely a massive violation of [asylum seekers'] rights."

9,000-person capacity

There are an estimated 54,000 African asylum seekers in Israel, with most coming from Sudan and Eritrea.

The Israeli government says African migrants are a burden on the state, and threaten its Jewish character. The country's policies, state officials have said, aim to deter the arrival of refugees at Israel's borders, and deport the ones that already live in the country.

According to a report in Israeli daily Ha'aretz, the new detention facility can currently hold up to 1,000 people, but it is expected to expand to accommodate 3,300 within the next two months.

"We hope it will eventually hold 6,000 or even 9,000 people," Yitzhak Aharonovitch, Israel's Public Security Minister, said.

The state said it would also provide African migrants held in the new centre with a monthly stipend, health services and educational training.

But asylum seekers are not convinced.

"There is no-one that can claim that he or she is safe in Israel... Everybody is afraid here. We are not secure," Haile Mengistaab, the head of the Eritrean Community Committee in Israel, told Al Jazeera in November.