United Nations Secretary-General Ban Ki-moon appealed for calm in Turkey on Friday as the world body sought to clarify the situation in the country, said a UN spokesman.
"The Secretary-General is closely following developments in Turkey. He is aware of the reports of a coup attempt in the country. The United Nations is seeking to clarify the situation on the ground and appeals for calm," said spokesman Farhan Haq.
The United States called on all parties in Turkey to support President Tayyip Erdogan's government against a coup attempt as world leaders expressed concern about the upheaval in a NATO member country that bridges Europe and the Middle East.
President Barack Obama and Secretary of State John Kerry spoke by phone and gave their support to Erdogan after Turkey's military said it had seized power on Friday. By early Saturday, Erdogan appeared to have regained control.
This as President Obama will hold a meeting of his national security and foreign policy team on Saturday to discuss the situation in Turkey, the White House said in a statement
European Council President Donald Tusk called for a swift return to Turkey's constitutional order, saying tensions there could not be resolved by guns.
"Turkey is a key partner for the European Union. The EU fully supports the democratically elected government, the institutions of the country and the rule of law," Tusk said at regional summit in Mongolia.
German Chancellor Angela Merkel echoed the sentiments.
"The democratic order in Turkey must be respected. Everything needs to be done to protect human lives," Merkel's spokesman Steffen Seibert said on Twitter.
Merkel condemned the Turkish attempted military coup and said Berlin stood by those who defended democracy and the rule of law in Turkey.
Iran, a Shi'ite Muslim nation which has long been a regional rival to Sunni majority Turkey, said on Friday it was deeply concerned about the crisis in the neighboring country.
"Stability, democracy and safety of Turkish people are paramount. Unity and prudence are imperative," Foreign Minister Mohammad Javad Zarif said on his Twitter account.
Iran's Supreme Leader Ayatollah Ali Khamenei said on Saturday that Tehran supported the Turkish government against a coup attempt despite regional disputes between the two countries, especially over Syria.
In Syria, hundreds of cheering government supporters took to the streets of Damascus early on Saturday and celebratory gunfire erupted after Turkey's army said it seized power from Erdogan, one of Syrian President Bashar al-Assad's main foes in the region.
On the other hand, Syrian rebels praised Turks for standing firm against a "conspiracy" to overthrow Erdogan, one of the main regional supporters of their fight against al-Assad.
"We congratulate the Turkish government...for the victory of the Turkish people and the government they elected," said a statement issued in the name of the Free Syrian Army (FSA).
Residents said convoys of cars circled around the Mazzeh district of the Syrian capital, with people waving flags and shouting: "God, Syria and Bashar!". There were similar celebrations in other government-held cities.
The Kremlin said it was gravely concerned about events in Turkey, and that it had instructed officials to help Russian nationals in Turkey return home at the earliest opportunity.
Kremlin spokesman Dmitry Peskov told reporters on a conference call that President Vladimir Putin was being kept constantly updated on the situation in Turkey.
China's Foreign Ministry called on Turkey to restore order and stability as soon as possible after the coup attempt, while Japanese Prime Minister Shinzo Abe said Turkey's democracy must be respected, according to the Kyodo news agency.
Britain's new foreign minister, Boris Johnson, said he was "very concerned" by events in Turkey, where many thousands of British and other European holiday-makers were spending summer vacations.
Pakistan condemned the attempt to undermine democracy and rule of law and China's Foreign Ministry called on Turkey to restore order and stability as soon as possible.
Mexico, Japan, South Korea and India also urged nationals not to travel to Turkey, while countries including Malaysia, Australia and New Zealand urged citizens in Turkey to be vigilant, stay indoors and keep tabs on local media.
Qatar condemned on Saturday an attempted military coup and said the emir telephoned Turkish President Tayyip Erdogan to express support for measures taken by the government to maintain stability in the country.
"The state of Qatar expressed its strong denunciation and condemnation of the military coup attempt, lawlessness, and violation of the constitutional legitimacy in the Republic of Turkey," Qatar's Foreign Ministry said in a statement.
The Qatari state news agency said the emir, Sheikh Tamim bin Hamad al-Thani, telephoned Erdogan to "congratulate him for the support the Turkish people have shown around Turkey's leadership".
"His highness also expressed strong condemnation and denunciation of this failed attempt and Qatar's stand and solidarity with the brotherly Turkish republic in all measures it is taking to protect the constitutional legitimacy and implement the law...," it added.
Other Gulf Arab countries have yet to comment publicly on the coup attempt, but some have urged citizens in the country to stay home and to remain in contact with diplomatic missions.
Saudi Arabia's national carrier said on Saturday it had suspended all flights to Turkey until further notice.
The kingdom welcomed Erdogan's success in prevailing against a coup attempt, state news agency SPA quoted a foreign ministry official as saying on Saturday.
"The source expressed the kingdom's welcome that things are returned to normal led by his Excellency President Tayyip Erdogan and his elected government and in line with the constitutional legitimacy and the will of the Turkish people," SPA said.
The head of Turkey's main opposition, the secular Republican People's Party (CHP), denounced the failed coup attempt by a faction of the military, and said its defeat brought political parties closer to finding common ground to improve democracy.
Kemal Kilicdaroglu made the comment in a speech to parliament.
The Turkish four main political parties also condemned the coup in a joint statement on Saturday, marking a rare departure from usually fractious politics.
The four parties, which run the gamut from the right-wing, Islamist-rooted AK Party founded by President Tayyip Erdogan to the left-of-center, pro-Kurdish Peoples' Democratic Party (HDP), said their stance was invaluable for democracy in Turkey.
REUTERS