CARACAS (Reuters) - A senior diplomat representing Venezuela at the United Nations in New York has broken with President Nicolas Maduro over abuses during anti-government protests, opening another crack in the unpopular leftist’s administration.

Isaias Medina appeared in a video circulating on Thursday, saying he was leaving the U.N. mission to “fight impunity” in Venezuela, which is heaving from a brutal economic crisis and nearly four months of street protests.

“I would like to call on this government to stop the killings, to stop the violation of human rights, to reconsider and reflect on their position and think about the importance of the country as a whole,” said Medina, who appeared to be speaking in the video from the U.N.’s New York headquarters.

“They (the government) can do whatever they want, but know this: What I am doing is the correct thing to do, and I assume full responsibility for it.”

Reuters was not immediately able to contact Medina, who served as minister counselor.

Venezuela’s ambassador to the United Nations Rafael Ramirez said Medina had acted in a “dishonest” way and been fired.

“I strongly and categorically reject the declarations and position taken up by the ex-official at our mission,” Ramirez, the formerly powerful head of Venezuela’s oil company, tweeted.

“He does not represent us. He has behaved in a dishonest manner.”

Medina’s dissent adds to a stream of outcry from ruling Socialist Party supporters since protests broke out in early April.

Most notably, chief state prosecutor Luisa Ortega has broken with Maduro. The defections have not turned into a torrent, however, and Maduro retains the backing of the powerful military’s top brass.