Jim Michaels

USA TODAY

U.S. air operations at Turkey's Incirlik air base — critical in the fight against the Islamic State — resumed Sunday, a day after the flights were cancelled because of an attempted military coup, the Pentagon said.

The base was reopened as the Justice Ministry announced that Turkey has detained about 6,000 people in connection with the failed coup. Justice Minister Bekir Bozdag said the number could grow.

"After close coordination with our Turkish allies, they have reopened their airspace to military aircraft,” Pentagon Press Secretary Peter Cook said in a statement.

“As a result, counter-ISIL coalition air operations at all air bases in Turkey have resumed,” he said, using an acronym for the Islamic State.

Turkey is a vital partner in the U.S.-led coalition’s war against the Islamic State in Iraq and Syria. The attempted coup raised concerns that political instability there could set back the fight against the militant group.

Beginning last year, Turkey has allowed U.S. aircraft to use the base to conduct airstrikes against the Islamic State, a move that placed attack planes and refueling aircraft closer to targets in Iraq and Syria, both of which border Turkey.

On Saturday, as the coup collapsed, Turkey had closed its airspace to military aircraft, forcing the U.S.-led coalition to rely more on other bases to launch strikes.

Turkey detains 6,000 in coup crackdown

The continued use of Incirlik suggests that Turkey’s commitment to the fight against the Islamic State won’t waver, at least in the short term.

But Turkish President Recep Erdogan has begun a purge of officers suspected of participating in or supporting the coup, which has raised worries that the government’s commitment to the fight may erode over time as it grapples with internal dissent.

Turkey's Justice minister said in a television interview Sunday that he was confident the United States would extradite Islamic cleric Fethullah Gulen, who lives in exile in Pennsylvania.

Erdogan alleged that Gulen, 75, a one-time political ally who had a falling out with the Turkish president, was behind the coup and called for his extradition. Gulen denied any involvement in the plot on Saturday.