Zambia’s security agencies have arrested several suspects accused of plotting to interfere with the electoral system ahead of Thursday’s elections, the interior ministry said.

In a statement on Wednesday, the ministry did not say how many people were arrested but said they included three former senior government officials accused of “providing technical services aimed at disrupting the electoral system”.

A 56-year-old Kenyan national was also taken into custody, it said.

Three other people, including a former provincial minister, were found in possession of more than 7.3 million kwacha ($388,000) and summoned to assist with the investigation.

“Investigations have also identified sensitive military intelligence information on some of the electronic devices seized from the trio,” Interior Ministry Permanent Secretary Dickson Matembo said.

A journalist and a former ambassador who had been detained in connection with the probe were later released, he said.

Zambians head to the polls Thursday to elect the president, members of parliament and municipal councillors.

President Hakainde Hichilema is seeking a second term as head of the copper-rich southern African nation, which has a long record of peaceful transfers of power through the ballot box.