Tunisian President Kais Saied's decision to suspend parliament and dismiss his prime minister sparked protests at home, where the biggest political party decried it as a "coup".
Foreign governments also voiced concern.
Here are reactions from countries and organisations around the world to Sunday's shock announcement and to further developments Monday, which also saw the sacking of the defence minister.
Washington voiced alarm and called on the birthplace of the Arab Spring to adhere to "democratic principles".
Later, US Secretary of State Antony Blinken spoke by telephone with Saied to urge respect for democracy and asked him to "maintain open dialogue with all political actors and the Tunisian people," the State Department said in a statement.
"He encouraged President Saied to adhere to the principles of democracy and human rights that are the basis of governance in Tunisia," it said.
"We call on all Tunisian actors to respect the constitution, its institutions and the rule of law," an EU spokesperson said.
"We also call on them to remain calm and to avoid any resort to violence in order to preserve the stability of the country."
Arab League chief Ahmed Aboul Gheit in a phone call with the Tunisian foreign minister expressed "complete support for the Tunisian people".
A statement said the Cairo-based league hoped Tunisia would "move swiftly past the current turbulent phase in restoring stability".
Kremlin spokesman Dmitri Peskov said Russia was monitoring developments in Tunisia.
"We hope that nothing will threaten the stability and security of the people of that country," he told reporters.
Paris urged a return "as soon as possible" to the "normal functioning" of government in Tunisia.
The foreign ministry called "on all of the country's political forces to avoid any form of violence and to preserve the country's democratic gains".
The foreign ministry in the Gulf state of Qatar expressed "hope... that the Tunisian parties would adopt the path of dialogue to overcome the crisis".
Saudi Foreign Minister Prince Faisal bin Farhan stressed "the kingdom's keenness on the security, stability and prosperity of Tunisia", during a phone call with his Tunisian counterpart.
The foreign ministry said it was "deeply concerned" and called for the restoration of "democratic legitimacy" in Tunisia.
President Recep Tayyip Erdogan's spokesman, Ibrahim Kalin, tweeted: "We reject the suspension of the democratic process and the disregard of the people's democratic will in friendly and brotherly Tunisia.
"We condemn initiatives that lack constitutional legitimacy and public support. We believe Tunisia democracy will emerge stronger from this process."
Jordan's Foreign Minister Ayman Safadi on Twitter expressed hope "that our brothers will overcome these difficult situations in a way that preserves the safety, security and stability of Tunisia".
A spokeswoman for the foreign ministry, Maria Adebahr, told reporters that Germany hoped Tunisia would return "as soon as possible to constitutional order".
"Democracy has taken roots in Tunisia since 2011", Adebahr said, referring to the year of the popular revolution that toppled dictator Zine El Abidine Ben Ali.
Germany was "very worried" she said, adding however: "We don't want to speak of a coup d'etat".
Amnesty International urged Saied to "publicly commit to respecting and protecting human rights, including the rights to freedom of expression, association and peaceful assembly".
It also denounced as "outrageous" Monday's forced closure of television network Al Jazeera's Tunis bureau, calling it a "deeply worrying precedent signalling that human rights are in danger".
Media watchdog Reporters Without Borders (RSF) also denounced the security forces' raid on Al Jazeera.
"We demand the immediate reopening without delay of the bureau and the return to normal working conditions for journalists," a statement said.