Turkish Prime Minister Recep Tayyip Erdogan, right, shakes hands with U.S. Vice President Joe Biden during a ceremony in Washington, D.C., on May 16, 2013, as Biden's wife Jill and U.S. Secretary of State John Kerry look on.

STUTTGART, Germany — Turkish police blocked access to Incirlik Air Base late Saturday in response to an anti-American protest, the second such rally in three days and a signal that the strategic base is emerging as a fulcrum for post-coup fallout as tensions between Turkey and the U.S. intensify.

Speculation of a second coup quickly swirled Saturday among local media as Turkish police in armored vehicles cut off access to Incirlik, but local officials dismissed the maneuver a “safety inspection."

“We did a general safety assessment. There is nothing wrong,” wrote Omar Celik, Turkey’s minister for European Affairs, in a Twitter post.

U.S. European Command said Sunday that Turkish authorities were on hand to offer security support.

“There was a small peaceful protest last night outside the Turkish Air Base Incirlik that Turkish police responded to; and the base gate was secured for a short time as a precaution,” said Navy Capt. Danny Hernandez, a EUCOM spokesman. “There was no impact to U.S. operations on the base.”

The rapid mobilization of Turkish police outside Incirlik served as a reminder that the country is still on edge in the wake of an attempted coup two weeks ago. About 2,500 U.S. troops are based at Incirlik, which is a key hub for counter Islamic State operations in Iraq and Syria.

The small protest Saturday comes after a larger gathering on Thursday outside Incirlik Air Base that coincided with Turkish President Recep Tayyip Erodgan’s lashing out at Central Command’s Gen. Joseph Votel, whom he accused of siding with coup plotters.

“It’s not up to you to make that decision. Who are you? Know your place,” Erdogan said on national television Friday, a day after Votel said the coup attempt on July 15 and the jailing of Turkish military leaders could affect U.S. operations against the Islamic State group in Syria and Iraq.

Erdogan’s criticism is the latest sign of escalating tensions between the United States and its longtime strategic ally. The stakes are likely to continue to rise in connection with Erdogan’s demand for the return of a U.S.-based cleric accused of inspiring the failed coup against Turkey’s president.

Since the abortive coup, some senior Turkish officials and pro-government news outlets have repeatedly blasted the United States, claiming it covertly supported the mutiny. They have also accused Washington of “standing up for savages” by not extraditing Turkish Muslim cleric Fethullah Gulen. Ankara has blamed the cleric, who lives in Pennsylvania, for organizing the putsch — a charge he denies.

Washington’s categorical rejection of any U.S. role in the coup attempt has not stopped speculation in Turkey that the U.S. was somehow involved in the attempt to overthrow Erdogan.

On Friday, Votel issued a statement saying “any reporting” that he was involved in the failed coup was “unfortunate and completely inaccurate.”

“Turkey has been an extraordinary and vital partner in the region for many years. We appreciate Turkey’s continuing cooperation and look forward to our future partnership in the counter-ISIL fight,” Votel said, referring to the Islamic State group by an acronym favored in Washington.

Last Monday, the Yeni Safak newspaper published a front-page story accusing retired U.S. Army Gen. John Campbell of orchestrating the coup. Campbell, who retired in May after commanding NATO forces in Afghanistan, dismissed the allegations.

Such sentiments likely fueled the protest outside the Turkish-run installation at Incirlik on Thursday and Saturday.

U.S. military officials said neither rally hindered operations. But as tensions between Washington grow, some analysts have warned that Turkey could condition future U.S. access to the base on the extradition of Gulen, Erdogan’s longtime nemesis.

The ratcheting up in tensions with Washington coincides with Ankara’s efforts to build warmer ties with Russia.

NATO’s top military commander warned Thursday that he was keeping his eye on an meeting between Erdogan and Russian President Vladimir Putin, looking for any signs of authoritarian drift from a key NATO ally.

Erdogan is scheduled to fly to St. Petersburg on Aug. 9 to meet with Putin. The planned trip is a sign that the two countries are quickly mending ties that frayed after a Turkish fighter shot down a Russian bomber operating over Syria last year.

The downing on Nov. 24 of the Russian Su-24 bomber by a Turkish F-16 fighter provoked a fierce response from Putin, who severed an array of political and economic ties between the countries. Earlier in July, Erdogan issued a public apology — a key Russian condition for normalizing relations.

Erdogan’s cozying-up to Putin could further divide NATO allies over how best to respond to Russia’s growing assertiveness, in particular its takeover of Ukraine’s Crimean Peninsula two years ago and its support of separatists in that country’s eastern region.

Yet there is also an upside for NATO to moves by Ankara and Moscow to get past their dispute over the downed aircraft, officials said. It could ease operations against the Islamic State group in Syria, given that coalition and Russian forces operate in such close proximity there.

“We encouraged Turkey to try and recover from the shoot down and solve that problem with the Russians,” Army Gen. Curtis M. Scaparrotti, head of U.S. European Command and NATO’s supreme commander, told the Aspen Security Forum on Friday. “It is positive they are beyond that now.”

But he added a key caveat.

“From my point of view, I would be concerned if it appeared they (Turkey) were departing from their values,” Scaparrotti said. “That is the bedrock of the Washington Treaty and NATO, which they are a part of — rule of law, democratic institutions, etc. So we will watch closely and hope that goes in the right direction.”

Scaparrotti’s comments came amid a widespread crackdown against government opponents in Turkey that followed the military mutiny. During the past two weeks, thousands of military officers and soldiers have been arrested, scores of judges detained and dozens of media organizations shut down.

Turkey has long been a difficult but important ally to the U.S.

The country is at the crossroads between Europe and the Middle East, putting it on the front lines of counterterrorism efforts and making it a key player in containing the flow of migrants into Europe.

Turkey has had several military coups since 1960, but until now none of them have affected or called into question the existence U.S. military installations in the country.

Stars and Stripes reporter Slobodan Lekic contributed to this report.

vandiver.john@stripes.com