(Refiles to add ‘stoking’ to headline)

* Trump tweets about S.Africa “farm seizures”

* S.Africa says Trump “misinformed”

* US diplomat summoned by South African ministry

* President Ramaphosa has announced new land reforms

* Land is highly-contested issue in South Africa

* S.Africa very unequal 24 years after end of apartheid

WASHINGTON/JOHANNESBURG, Aug 22 (Reuters) - South Africa on Thursday accused U.S. President Donald Trump of stoking racial divisions in a late-night tweet in which he said he had asked Secretary of State Mike Pompeo to study South African “land and farm seizures” and the “killing of farmers”.

Washington’s charge d’affaires in South Africa, Jessye Lapenn, was summoned by the ministry of foreign affairs over the tweet, people familiar with the matter told Reuters.

Trump’s comments inflamed an already high-octane debate over land in South Africa, a country that remains deeply racially divided and unequal nearly a quarter of a century after Nelson Mandela swept to power at the end of apartheid.

The rand currency dropped more than 1.5 percent against the U.S. dollar in early trade on Thursday after Trump’s tweet had circulated in South Africa, before trimming its losses.

“I have asked Secretary of State @SecPompeo to closely study the South Africa land and farm seizures and expropriations and large scale killing of farmers,” Trump said on Twitter.

The tweet appeared to be a response to a Fox News report on Wednesday that focused on South Africa’s land issue and murders of white farmers.

South African President Cyril Ramaphosa’s spokeswoman said Trump was “misinformed” and the foreign ministry would seek clarification from the U.S. Embassy in Pretoria.

“South Africa totally rejects this narrow perception which only seeks to divide our nation and reminds us of our colonial past,” a tweet from South Africa’s official government account said.

Ramaphosa announced on Aug. 1 that the ruling African National Congress (ANC) plans to change the constitution to allow the expropriation of land without compensation, as whites still own most of South Africa’s territory.

Ramaphosa has said any measures would not hit economic growth or food security. No land has been “seized” since the reform plans were announced, the ANC says.

“It is regrettable that the tweet is based on false information,” South Africa’s foreign affairs minister, Lindiwe Sisulu, said.

Far-left opposition firebrand, Julius Malema, who has led calls for the seizure of white-owned land, told Trump to keep out of the debate. “We want to send a strong message to the U.S. to stay out of South Africa. You have caused enough problems in Africa,” he told journalists.

The U.S. State Department said it would respond during a briefing by spokeswoman Heather Nauert later on Thursday.

AfriForum, which mostly champions white people’s rights in South Africa, welcomed Trump’s announcement.

“Everyone in South Africa should therefore hope that the pressure from the USA will lead to the ANC reconsidering the disastrous route that they want to take SA on,” AfriForum’s CEO, Kallie Kriel, said.

He added that Trump’s comment came just three months after the organisation sent a delegation to the United States to brief Fox News presenter Tucker Carlson, and the Cato Institute think tank, on the situation in South Africa.

VIOLENT CRIME

Violent crime is a serious problem across South Africa and 47 farmers were killed in 2017-18, according to statistics from AgriSA, an association of agricultural associations. However the same figures show that farm murders are at a 20-year low.

Since the end of apartheid in 1994, the ANC has followed a “willing-seller, willing-buyer” model under which the government buys white-owned farms for redistribution to blacks.

Progress has been slow and most South Africans believe something has to be done to accelerate change, providing it does not hurt the economy or stoke unrest.

“Reforming the land distribution and ownership will be good for South Africa,” said political analyst Nic Borain.

“That there will be instability and worries about property rights is inevitable, but we don’t expect that the government will act in a way that radically destabilises investor security.”

Trump’s tweet came days after it was announced that his wife, Melania, would travel to Africa in October for her first major solo international trip as first lady.

In January, South Africa protested to the U.S. Embassy in Pretoria about reported remarks by Trump that some immigrants from Africa and Haiti came from “shithole” countries. (Editing by James Macharia, Andrew Heavens and Susan Thomas)