(Bloomberg) -- Guatemala’s dollar bonds lost the most among emerging-market sovereigns on Monday as attempts to overturn the presidential election result risk making the nation an international pariah. 

Bonds sank across the curve, with notes due in 2050 falling 1.8 cents to 85 cents on the dollar, the biggest drop in more than two months. The rout came after prosecutors called for the invalidation of Bernardo Arevalo’s election victory a month before he’s due to be sworn in as president.

The US stepped up pressure on those attempting to block Arevalo from taking power, imposing sanctions on nearly 300 Guatemalans, including more than 100 members of congress, for “undermining democracy and the rule of law.” 

State Department spokesman Matthew Miller said Monday that the US “strongly condemns ongoing anti-democratic actions” by “malign actors.”   

Read more: State Dept: Additional Steps Taken in Response to Anti-Democratic Actions in Guatemala

The request by Guatemalan prosecutors poses the biggest threat yet to Arevalo’s inauguration scheduled for Jan. 14. The US and the European Union have repeatedly criticized attempts to keep Arevalo out of office. 

Given the risks, investors should be cautious about buying the dip, Barclays strategists Nestor Rodriguez and Jason Keene wrote in a note on Monday. 

“The international community’s forceful rebuke shows that any break in the democratic order would likely be widely condemned and Guatemala could quickly become a pariah state,” they wrote. 

Arevalo won the August election pledging to crack down on corruption. 

Prosecutors on Friday called for annulling the 2023 election for president, vice-president and congress, saying there were a series of violations in the vote count. 

US Assistant Secretary of State Brian Nichols said in a post on X “such actions jeopardize Guatemala’s market-friendly reputation and will be met with a strong U.S. response.” 

Arevalo called the case a “perverse, ridiculous and absurd” coup attempt and insisted he will take office in January. In recent weeks, his supporters have frequently taken to the streets to defend his election win. 

The head of the nation’s electoral body, Blanca Alfaro, said only the constitutional court can overturn the election, which has already been certified.

(Adds US sanctions on individuals in 3rd paragraph.)

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