Donald Trump has asked his secretary of state, Mike Pompeo, to “closely study the South Africa land and farm seizures” and the killing of farmers there.

Trump posted a quote from Fox News on Twitter alleging the South African government was “seizing land from white farmers”.

The president’s tweet and his direction to his secretary of state seem to have been prompted by a segment on Fox News on Wednesday night in which host Tucker Carlson expounded on the seizures. Trump tagged Carlson in his tweet.

Land ownership is a deeply divisive issue in South Africa: 72% is in the hands of white farmers, according to the Land Audit Report, despite just 8% of the country’s population of 56 million being white.

All major political parties have agreed on the need for extensive land reform, and on 1 August the president, Cyril Ramaphosa, announced that the ruling African National Congress would forge ahead with plans to change the constitution to allow the expropriation of land without compensation, a motion passed by parliament in February.

Trump is the latest in a string of leaders to have taken up the cause of white South African farmers this year.

In March this year, Peter Dutton, then home affairs minister for Australia, who has this week challenged Malcolm Turnbull to become prime minister, announced that white farmers from South Africa “deserve special attention” from Australia and that his department was examining a range of methods to fast-track visas for them.

The South African government said it was offended by Dutton’s statements and demanded a retraction.

Earlier this year Katie Hopkins, the former British columnist and reality TV show contestant, crowd-funded a trip to South Africa where she interviewed white farmers about violence they had suffered.

Trump repeated the rhetoric of South African farmers being particularly vulnerable to violence. However, according to research by one of South Africa’s biggest farmers’ organisations, such murders are at a 20-year-low.

In 2017-18, 47 farmers were killed, according to statistics compiled by AgriSA, an association of hundreds of agricultural associations across South Africa. Violence against farmers peaked in 1998 when 153 died. Between 80 and 100 were murdered each year from 2003 to 2011, and around 60 until 2016.

Despite the decline in the number of fatalities there has been a rise in the number of attacks on farms, from 478 in 2016-17 to 561 a year later.

These figures have been challenged by other organisations representing farmers in South Africa but AgriSA said its research was “reliable”.