An opposition leader in Tanzania said he was taking death threats he received after he urged the World Bank to withdraw a $500m (£382m) education loan to the country over human rights concerns “very seriously”.

But Zitto Kabwe, leader of the alliance for change and transparency party (Act), added that he would not be intimidated by comments made by the leader of the ruling party and other officials that his request to the bank was an act of betrayal and he should be killed.

In a letter to the bank on 22 January, Kabwe urged board members to suspend any loans until “checks and balances” including a free press, free and fair elections, and the reinstatement of the controller and auditor general, were restored in the country.

“I don’t regret my words,” Kabwe told the Guardian. “I did the right thing. I defended young girls to be able to go to school.”

Kabwe, who is currently in Canada, added: “We just wrote a letter. We were just making a point. This reaction from the government should be a lesson for the World Bank. This is the sort of government they are dealing with.”

On 30 January the World Bank postponed for the second time a vote on the loan, aimed at improving access to secondary education, after opposition from Kabwe, Tanzanian activists and human rights groups.

Critics said the loan would endorse the government’s discriminatory policy of banning pregnant girls from school. A US executive director at the bank also expressed “deep concerns” over the policy, requesting more time for the bank’s board to discuss “serious gender equality” issues.

The head of international relations for Act said Kabwe had received a number of threats, in “direct retaliation” for his opposition to the loan.

In a letter to World Bank president David Malpass, seen by the Guardian, Act requested an assurance from the bank that any reprisals against Kabwe would “trigger a suspension of all World Bank operations and funding in the country”.

In parliament on 1 February Abdallah Bulembo, from the ruling Chama Cha Mapinduzi (CCM), reportedly called for Kabwe’s elimination, according to the BBC. His party colleagues stamped and applauded after his comments.

“There is one man who took our issues outside the country, he should not be allowed back but should be killed where he is,” he reportedly said. “Treason! What Mr Zitto Kabwe has been doing is treason in our country.”

Speaking at a party meeting over the weekend, CCM youth wing official Kenani Kihongosi was reported as saying people who “defamed” Tanzania deserved to be killed.

“We are fed up with a few useless people who are defaming our country but we are tired with those being used by colonialists,” he said. “I urge the youth to write about the good that the government is doing but also not to hesitate to criticise those who undermine our nation, they are our number one enemies and they deserve to be killed.”

Act said that CCM had been running a “systemic campaign” against Kabwe, which had taken “a dark and menacing tone”.

The country director for Tanzania at the World Bank is expected to meet government counterparts on Tuesday, and is expected to raise concerns.

In 2017 similar threats were made against another opposition MP, Tundu Lissu, before he was shot 16 times by unknown assailants, suffering life-changing injuries from which he is still recovering. No one was arrested for the crime.

In November 2018, the bank withdrew a $300m loan to Tanzania for secondary education, partly because of the country’s mistreatment of pregnant schoolgirls, as well as threats against members of the LGBT+ community.

Since John Magufuli became president in 2015, the government has forced girls to undergo pregnancy tests and excluded thousands of them from school. Press freedoms and opposition activity have also been restricted.