Thousands of protesters have flooded the streets of Guatemala, answering a call issued by President-elect Bernardo Arevalo to defend the integrity of the country’s recent elections.

Last Friday, Arevalo took to social media to rally his supporters, asking them to join him in Guatemala City on Monday as he filed a legal challenge against those he considers “coup-mongers”.

“The time has come for all of us together, as one nation, to step forward, raise our voices and put a stop to that corrupt and coup-mongering minority that tries to deny the people of Guatemala the right to live in democracy,” Arevalo wrote.

He also pledged to take his complaint to Guatemala’s Supreme Court of Justice: “We’ll see you in court!”

Ever since he emerged as one of two finalists in the June 25 presidential election, Arevalo — a dark-horse candidate who campaigned on combatting corruption — has seen his presidential ambitions beset by challenges from the political establishment.

He has continued to be a target even after winning the August 20 run-off in a landslide.

Critics fear that actions taken under figures like Guatemala’s attorney general, María Consuelo Porras, are a ploy to derail his election victory and scuttle the will of the voters.

The United States has previously sanctioned Porras for “her involvement in significant corruption”. After Arevalo became a frontrunner on June 25, Porras’s office opened an investigation into his political party, the Seed Movement, claiming signatures collected years ago to form the party were fraudulent.

Her office also sent police officers to raid the Seed Movement’s headquarters, as well as the offices of Guatemala’s Supreme Electoral Tribunal.

Officials with the tribunal have criticised the raid as unlawful. Police officers reportedly opened boxes containing ballots from the race, a move critics say violates voters’ privacy and compromises the integrity of the elections.

The attorney general’s office has defended its actions as a check against voter fraud, though nonpartisan election observers have denied there is any evidence of widespread malfeasance.

On Monday, US Ambassador Francisco Mora denounced the “anti-democratic behavior” he observed in Guatemala’s Public Ministry and other government bodies since Arevalo victory.

“In a healthy democracy, institutions don’t tamper with ballot boxes after election results have been officially certified by the appropriate authority,” Mora said in a statement.

Already on Monday, CODECA — a nationwide organisation representing rural Indigenous communities — announced it would block roadways to protest the alleged election interference, starting on the next day. It also called on the judges and prosecutors involved to resign.

Meanwhile, in Guatemala City, Indigenous leaders and other protesters marched through the streets with signs that condemned the recent actions as a “coup”.

Arevalo himself appeared alongside his running mate, Karin Herrera, in Guatemala City’s Human Rights Plaza as he prepared to present his complaint in person at the Supreme Court.