South Sudanese activist Peter Biar Ajak, who has been a critic of the country's government, has fled to the US.

He said in a tweet that a death squad had been sent to kill him.

THANK YOU @SecPompeo & @StateDept officials in D.C., Nairobi & Juba 4 helping my family and me get refuge in the USA after I fled a death squad sent by #SouthSudan President Salva Kiir. Kiir has ruled 9 yrs with an iron fist never facing an election - they MUST happen in Dec ‘21.

— Peter Biar Ajak (@AjakPeter) July 24, 2020

The government has denied the allegation, Reuters reports quoting a presidential aide.

“That is complete nonsense. He was here when he was pardoned by the president and allowed to go abroad. He should not associate anything that comes his way with the government of South Sudan,” Ateny Wek Ateny, South Sudan’s presidential press secretary, told Reuters in the capital, Juba.

Mr Ajak was arrested in July 2018 and sentenced to two years in prison in June 2019. He was pardoned by President Salva Kiir and released from prison in January.