TURKEY -- The Turkish government says it's back in control after Friday's failed military coup caused a night of explosions, air battles, and gunfire, but there are still many questions about security and stability in the country.

Turkish officials are urging supporters to come out to city squares to defend democracy.  Massive crowds filled the streets Saturday night to show their support of the Turkish government. Many chanted and waved flags as they marched.

Nearly 300 people were killed and hundreds more injured during the attempted coup when bombs were thrown at the parliament building, military tanks blocked streets and bridges, and gunfire continued well into Saturday morning.

Turkish President Recep Tayyip Erdogan addressed crowds in Istanbul Saturday, and he declared his government was in control after the attempted coup.

Erdogan also asked the U.S. to extradite a Muslim cleric he blames for the coup.  That cleric, Fethullah Gulen, lives at a religious retreat center in Pennsylvania. Gulen leads a Turkish populist movement, but says he's been out of Turkey for 16 years and has nothing to do with the coup.

Secretary of State John Kerry says the U.S. could consider the extradition request if the Turkish government presents legitimate evidence of the cleric's involvement. HE also reiterated his and the president's support for Turkey.

"The United States, without any hesitation, squarely and unequivocally, stands for democratic leadership or respect for democratically elected leader, for any Constitutional process with that regard, and we stand by the government of Turkey," Kerry said.

It is still unclear exactly who is behind the coup and why they decided to act now.

Just hours after it began, thousands of military officials were arrested, including some top-ranked officers. Many more would later surrender.