BANGKOK: Thai Prime Minister Paetongtarn Shinawatra faced mounting calls Thursday to resign after a leaked phone call she had with former Cambodian leader Hun Sen provoked widespread anger and prompted a key coalition partner to quit.

The coalition government led by Paetongtarn’s Pheu Thai party appears on the brink of collapse, throwing the kingdom into a fresh round of political instability as it seeks to boost its spluttering economy and avoid US President Donald Trump’s swinging trade tariffs.

The conservative Bhumjaithai party, Pheu Thai’s biggest partner, pulled out on Wednesday saying Paetongtarn’s conduct in the leaked call had wounded the country and the army’s dignity.

Thailand’s foreign ministry said Cambodia’s disclosure of a recording of a private conversation between Prime Minister Paetongtarn Shinawatra and former Prime Minister Hun Sen were unacceptable.

“It is a breach of diplomatic etiquette, a serious violation of trust, and undermines conduct between two neighboring countries,” spokesperson Nikorndej Balankura said on Thursday.