Access to the social media platform X has been restricted in Tanzania after some official accounts of government and private institutions were targeted by hackers.

On Tuesday, the official police account was compromised, with sexually explicit material and false information that the president had died being posted.

The police dissociated itself from the information and said an investigation was under way to identify those responsible.

Hours later data from the internet monitoring organisation Netblocks showed that X was "unreachable on major internet providers" across the country.

Users in Dar es Salaam, the country's biggest city, could still not access the site on Wednesday, unless they use virtual private networks (VPNs), which is illegal without a permit, although some people in other regions indicated they were able to log on.

The authorities have not commented on whether they are blocking access to X.

But Information Minister Jerry Silaa has acknowledged the hacking and assured MPs in parliament that the affected government social media accounts had since been secured.

Earlier, government spokesman Gerson Msigwa warned those responsible that immediate action was being taken.

The problems with accessing X come amid the continued uproar over the deportation of prominent Kenyans - a move that prevented them from attending the court case of opposition leader Tundu Lissu, who is accused of treason.

On Monday, the president warned activists from its northern neighbour that she would not allow them to "meddle" in her country's affairs and cause "chaos".

She spoke after Kenya's former Justice Minister Martha Karua along with some others, who had all travelled to attend Lissu's court case, were deported.

Another Kenyan activist, Boniface Mwangi, and Ugandan Agather Atuhaire were arrested in Dar es Salaam by suspected military officers on Monday and their whereabouts remain unknown.

Tanzanian authorities have not commented on their whereabouts.

Mwangi's wife, Njeri, told the BBC's Newsday programme that she had last heard from him on Monday and had not been able to establish where he was.

"I'm actually concerned for his life. I know my husband, he would have communicated, he'd find a way to call or text me and because he hasn't, makes me very worried about what state he is in," she said.

Boniface Mwabukusi, the president of the Tanganyika Law Society, the body representing lawyers in mainland Tanzania, said on Wednesday that they had learnt that the two were being held by the immigration department. He had earlier said they had been deported.

"Our legal team on the ground is actively monitoring the situation and exploring appropriate legal remedies to facilitate a just and timely resolution," he said on X.