Tanzania’s Home Affairs Ministry has initiated yet another crackdown on illegal immigrants, targeting its borders with the Great Lakes region.

Home Affairs Minister Kangi Lugola has ordered immigration officials to conduct house-to-house searches in Kagera and Kigoma regions, which border Uganda, Rwanda, Burundi, and the Democratic Republic of Congo.

The operation is expected to be completed in time for local government (civic) elections in the targeted regions, which are scheduled for July, Mr Lugola said in his directive to Commissioner General of Immigration Anna Makakala.

The operation will also involve a fresh verification of national identity cards issued to residents of those regions over the past few years.

Speaking at a public rally in Karagwe district, near the border with Uganda, the minister also warned immigration officials against taking bribes.

“Be warned, if I get hold of such an officer, there will be no mercy…. Their job is gone,” he said.

Dealing with illegal immigrants has been a thorny problem in Tanzania’s border regions, with Kagera in the northwest, Kigoma in the west, Rukwa in the southeast and Mara in the north as the most affected.

Last week, police in Morogoro detained 11 illegal migrants from Somalia being transported to Iringa in a Toyota minivan.

On December 10, Ethiopian illegal migrants were intercepted crammed behind the driver’s seat of a cargo truck in Songwe region. The truck was transporting imported petrol from Dar es Salaam to Zambia.

Days earlier, 26 immigrants from the same country — half of them already dead —had been found abandoned in a cargo container on the Morogoro-Iringa highway.

Most of the immigrants enter Tanzania through official and unofficial channels, including unregistered entry points, but there have been many cases of human trafficking.

Some escape from refugee camps while others enter the country as nomadic pastoralists. In most cases, they are hired by the local communities as domestic or farm workers.

There has been a proposal that immigrants who have resided in Tanzania for a long time be subjected to "special screening" to determine their levels of loyalty and potential for citizenship.

Authorities say they are endangering the country’s social and economic stability, while also posing security risks.

Figures released by the Immigration Department last week show that 12,600 illegal migrants were arrested in various parts of the country between January and November last year, the majority being Burundian and Mozambican. Of those, 6,918 were repatriated while 2,499 were charged in the courts for violating the country's immigration laws.

"The illegal immigration problem is not just confined to Tanzania... it's worldwide, and that's why we deport most of them to their home countries rather than prosecute them in court for breaking the law," said Immigration Department spokesman Ally Mtanda.

The department cited Burundi, DRC and Nigeria as countries whose nationals were denied entry into Tanzania between January and November last year. Kenya was fourth on the list, with 32 denied entry.

In January last year, immigration authorities in the northern Kilimanjaro region carried out a rare mass deportation of verified illegal immigrant settlers who included 71 Kenyans, seven Rwandans, seven Congolese, five Ethiopians, two Ugandans, one Somali, and one Nigerian, saying they would only be allowed back if they followed lawful migration procedures.

“We discovered that some of them entered the country as far back as 1972, and had been living here unlawfully for all these years,” Kilimanjaro regional immigration boss Albert Rwelamira was quoted as saying at the time.