The United Nations Secretary-General Ban Ki-moon has expressed deep concern over the military coup in the South African nation of Lesotho, calling on all parties to resolve their differences peacefully.

“He calls for respect for the constitutional order and democratic rule. He urges all parties to refrain from violence and work together towards a peaceful and lasting resolution of their differences,” Ban’s Spokesman Stéphane Dujarric said in a statement released on Sunday.

The UN chief also welcomed earlier efforts by the regional bloc known as the Southern African Development Community (SADC), the Commonwealth and other partners of Lesotho to support the restoration of trust among the members of the country’s coalition government, and urged all parties to continue to play an active role in the promotion of peace in Lesotho.

On Saturday, Lesotho’s Prime Minister Thomas Thabane fled to South Africa in fear for his safety after the army surrounded his residence and police stations in the capital Maseru, and gunshots rang out.

Thabane said he suspected his deputy Mothet Joa Metsing was involved.

The army denied trying to drive Thabane out of power, saying it had moved against police officers suspected of planning to arm a political faction in the small Southern African country.

Metsing also dismissed allegations of a coup. “I would not still be a deputy prime minister; the prime minister would not still be the prime minister if a coup [had] taken place,” he stated.

Thabane’s All Basotho Convention party and Metsing’s Lesotho Congress for Democracy formed a coalition with a third party, the Basotho National Party, after elections in May 2012.

Political tensions simmered high since then between Thabane and Metsing and within the coalition government. Thabane suspended parliament sessions in June amid feuding in his administration.

Regional power South Africa described the situation in Lesotho as “worrying,” with government spokesman Clayson Monyela saying his country would not tolerate “unconstitutional change of government” in the landlocked country.

Lesotho has seen a series of military coups since independence in 1966.