Guterres spoke by phone with President Maithripala Sirisena, who set off the crisis when he sacked prime minister Ranil Wickremesinghe on October 26 and replaced him with former authoritarian president Mahinda Rajapakse.
Sri Lanka will lose duty free access to the European Union if the country goes back to violating human rights, an ambassador has said, amid a political crisis sparked by a contested appointment of a new prime minister.
One correspondent asked whether the United States still considered Wickremesinghe "the legitimate prime minister" of Sri Lanka.
The most famous (or notorious) symbol of the burgeoning Sri Lanka-China cooperation is the port of Hambantota at the island's south, viewed as an important cog in the wheel of Beijing's One Belt One Road (OBOR) initiative, or a part of "String of Pearls" that Beijing seeks to create around its neighbour India in fight for regional, and ultimately, global dominance. But in 2015, Sirisena joined hands with Wickremesinghe and former President Chandrika Kumaratunga in a conspiracy orchestrated in Washington to remove Rajapakse. The mutual suspicions that each Great Power has of the other in this region stand in stark contrast to their recent rapprochement following last summer's Doklam/Donglang drama in the Himalayas.
Rajapaksa's party dismissed the allegation.
In a long address to the nation over the weekend, President Sirisena said tensions had been building up between him and his PM for years.
So, Rajapaksa has taken office?
Afghan forces struggle to regain ground as casualties mount
The Afghan government no longer releases exact casualty figures but this month General Joseph Votel, head of U.S. But SIGAR still acknowledged in its latest report that the death toll is at the highest its ever been.
Wickremesinghe and his party have maintained that the move was illegal as they still held a majority in the House.
Sirisena accused Wickremesinghe, a trained lawyer who favours a liberal economy, of being dictatorial and ignoring the president in cabinet. The president also alleged that a cabinet minister was involved in a plot to kill him and that police had obstructed an investigation. He tweeted: "the people's voices have been heard".
Negotiated during the tenure of Rajapaksa as President, the repayments for the port are said to have pushed Sri Lanka into a debt-trap.
A divorce of their coalition was inevitable after just over three years, Sirisena said.
"The constitution doesn't make provisions for personality clashes", he said. This amendment was introduced by both Mr Sirisena and Mr Wickremesinghe. Wickremesinghe was appointed prime minister.
Devi said she wanted to show solidarity after Wickremesinghe's government built 5,000 homes for people like her who were displaced by the civil war that ended in 2009.