U.S. President Barack Obama spoke by telephone with Secretary of State John Kerry on Friday night about events in Turkey and agreed that all parties there should support the democratically elected government, show restraint and avoid any violence or bloodshed, the White House said.
"The Secretary underscored that the State Department will continue to focus on the safety and security of U.S. citizens in Turkey. The president asked the secretary to continue to keep him updated as the situation unfolds," the White House said in a statement.
Presidential hopeful Hillary Clinton also called for support of turkey's elected civilian government.
Meanwhile, British Foreign Minister Boris Johnson said he was "very concerned" by events in Turkey.
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.
Iran said it was deeply concerned about the crisis in neighboring Turkey after reports of an attempted military coup there.
"Stability, democracy and safety of Turkish people are paramount. Unity and prudence are imperative," Foreign Minister Mohammad Javad Zarif said on his Twitter account.
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.
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.
Ties between Turkey and Germany - vital partners in efforts to curb mass migration to Europe - have been strained since the Bundestag passed a resolution in June branding the 1915 massacre of Armenians by Ottoman forces as a genocide. Ankara recalled its ambassador and threatened unspecified retaliation.
Qatar condemned on Saturday a military coup attempt in Turkey and said it supported legal measures taken by the Turkish 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," said a statement by Qatar's Foreign Ministry quoted by state news agency QNA.
The wealthy Gulf state, a key ally of Turkey, said violence should be rejected, Turkey's constitutional legitimacy preserved and the will of its people respected.
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.
Turkey's military said on Friday it had seized power but President Tayyip Erdogan vowed that the attempted coup would be put down.