The South African ambassador who was expelled from the US after a row with Donald Trump's government has said he has "no regrets".

Ebrahim Rasool arrived back home on Sunday and was welcomed by hundreds of raucous supporters at Cape Town International Airport.

Tensions between South Africa and the US have been on a downward spiral since Trump came into office in January.

Rasool, 62, was declared unwelcome in the US after Secretary of State Marco Rubio called him a "race-baiting politician who hates America".

It followed a statement by the ambassador that Trump was "mobilising a supremacism" as the States' white population faced becoming a minority.

Rasool defended his comments on Sunday morning after touching down in Cape Town.

The remarks, made during a webinar organised by a South African think tank, were meant to "alert" South African intellectuals and political leaders "to a change of the way we live, to a change of the way we are positioned in the United States, that the old way of doing business with the US was not a good one", Rasool said.

While waiting for Rasool to arrive at the airport, members of the African National Congress, South African Communist Party and trade unionists sang and danced.

Some held placards reading "Ebrahim Rasool, you have served our country with honour!!!"

Rasool's expulsion marked a rare move by the US - lower-ranking diplomats are sometimes expelled, but it is highly unusual for it to happen to a more senior official.

But ties with South Africa have been deteriorating for months.

In January, South African President Cyril Ramaphosa signed into law a bill allowing the state to seize land without compensation, provided it was in the "public interest".

The move followed years of calls for land reform, with activists and politicians seeking to redistribute farmland from the white minority.

In response to the law, Washington cut aid to South Africa. An executive order cited "unjust racial discrimination" against white Afrikaners - descendants of mainly Dutch settlers who first arrived in the 17th Century.

South Africa has strongly denied this claim.

On Sunday, Rasool lamented that he had not been able to challenge the Trump administration's views.

He was appointed as ambassador to the US just last year, because of his experience and extensive network of Washington contacts.

He had previously served as US ambassador from 2010 to 2015 when Barack Obama was president.