Zambian lawyer John Sangwa is challenging President Edgar Lungu’s eligibility to run in August elections arguing that he has already served two terms.
President Lungu’s first stint in office lasted 18 months when he was elected after the death of Michael Sata in 2014.
He was then re-elected in August 2016.
The governing Patriotic Front (PF) says Mr Lungu’s first tenure in office was not a full term as he was completing Mr Sata’s term.
The party has labelled Mr Sangwa “a political opponent”.
The lawyer told the BBC that he has received threats on his life but will continue with his push.
“So far, I am well and still going on with my daily routine. It’s very unfortunate when leaders come up and issue threats. Their focus should be coming up with a competent legal team and respond to what I have raised in the courts of law,” he said.
In 2018, a group of opposition parties went to court to seek an interpretation on whether Mr Lungu had served two terms. The Constitutional Court ruled the first one was not a full term.
Mr Sangwa’s petition argues that the constitution does not allow a person who has twice served as president to stand again – regardless of whether the first term was full or not.
In 2008, after Zambia’s former President Levy Mwanawasa died in office, his successor Rupiah Banda’s continuation was considered as his first term.
Zambians have taken to social media to support Mr Sangwa under the hashtag #IStandWithSangwa.
Zambia’s law association has also asked the governing party to apologise to the lawyer: