Zambian President Edgar Lungu reacts after participating in a discussion at the World Economic Forum on Africa 2017 meeting in Durban, South Africa May 4, 2017. REUTERS/Rogan Ward

LUSAKA (Reuters) - Zambia has asked Cuba to recall its ambassador for openly supporting the newly launched opposition Socialist Party, the president’s spokesman said on Sunday.

Amos Chanda said ambassador Nelson Pages Vilas spoke at the party’s launch on Saturday.

Political tensions were rekindled in Zambia last month when the country’s main opposition party, the United Party for National Development (UPND), filed a motion seeking to impeach President Edgar Lungu over accusations of breaching the constitution.

The UPND challenged Lungu’s 2016 election victory in court, alleging fraud, arguing that that obliged him to hand over power to parliament’s speaker until the court considered its petition.

Lungu has denied electoral fraud.

He directed that the Cuban ambassador be recalled “for behavior unbecoming of a diplomat,” Chanda told a media briefing, adding that diplomatic ties with Cuba would be retained.

Reuters was not immediately able to contact the ambassador for comment.