World Bulletin / News Desk

US President Barack Obama was huddling with top national security advisers in the White House Situation Room Saturday to address the destabilizing coup attempt in Turkey.

The government of Recep Tayyip Erdogan appears to have repelled the plot, but the situation remained fraught and tensions between Washington and Ankara appeared to be growing.

In a statement, the White House said that Obama had convened a meeting with "his national security and broader foreign policy team to update him on the situation in Turkey."

During the coup, Obama offered vocal support for Turkey's "democratically elected government" and urged all parties to "avoid any violence or bloodshed."

But there were growing concerns of a government crackdown on Erdogan's opponents.

German Chancellor Angela Merkel, a key Obama ally on the world stage, has urged Erdogan to deal with coup plotters under the rule of law.

The Turkish authorities have imposed a security lockdown and cut power to the Incirlik air base in southern Turkey which is used by US forces.

Separately, a US defense official said that American forces across Turkey had been placed on maximum alert.

In public appearances since returning to Istanbul, Erdogan has blamed the putsch on followers of Pennsylvania-based opposition figure Fethullah Gulen, a Turkish preacher with a large following.

State John Kerry on Saturday said the United States will help Turkey investigate the failed coup and he invited Ankara to share any evidence it has against Gulen.

He added that Turkey had not yet issued a formal extradition request.

Even before Friday's bloody drama, Obama had voiced concern about Erdogan's treatment of the press and his respect for the rule of law.