The SDLP has said a former leader who appeared on Russian state-backed media "does not represent" the party after his successor Colum Eastwood slammed politicians who contribute to the news channel.
Mr Eastwood criticised politicians who have taken part in programmes on Russia Today, claiming it amounted to support for Vladimir Putin's regime.
Senior representatives of parties including Sinn Féin and the DUP have previously appeared on the channel, which is being banned by the European Union for "harmful disinformation" in response to Russia invading Ukraine.
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Among the Irish political figures who took part in RT programmes were Sinn Féin leader Mary Lou McDonald and the party's South Down MP Chris Hazzard.
Earlier this month Mr Eastwood's predecessor, former SDLP leader Alasdair McDonnell, also appeared on the channel.
The former South Belfast MP was interviewed on the Alex Salmond Show, which is aired on RT International and hosted by the ex-leader of the SNP.
DUP Strangford MP Jim Shannon appeared on the same programme as they discussed party MLA Paul Givan's resignation as Stormont First Minister over Brexit's Northern Ireland Protocol.
In a tweet at the weekend, Mr Eastwood said: "Political figures here repeatedly appeared on RT when they knew what Putin and his gangster regime were doing. It amounted to support for the regime."
The Foyle MP asked whether those who took part in the channel would now apologise, and if any money received from RT would be given to "charities helping the Ukrainian people".
The SDLP said the party and its elected representatives have "consistently declined requests" to appear on RT, branding the media outlet as a "propaganda tool of Putin's regime".
A party spokesman said: "The SDLP is very clear that RT is a propaganda tool of Putin's regime and anyone appearing on the channel wrongly lends legitimacy to their narrow imperialist agenda.
"The party and its elected representatives have consistently declined requests to appear on RT programming in solidarity with those oppressed by the Putin regime.
"In the interests of supporting the Ukrainian people our position is that all those who have received an appearance fee for RT programming should make a donation to causes providing humanitarian aid in the country.
"Politicians cannot claim to stand with Ukraine if they are also taking money from Putin's regime.
"Alasdair McDonnell is a private individual and does not represent the SDLP."
It is understood Mr McDonnell would not have received any appearance fee for his interview on RT.
Sinn Féin, the DUP, Mr McDonnell and the makers of the Alex Salmond Show were approached for comment.
European Commission president Ursula von der Leyen announced plans to ban Russia's state-owned news outlets RT and Sputnik as part of further sanctions on Russia.
"We are developing tools to ban their toxic and harmful disinformation in Europe," she said.
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