Turkish President Recep Tayyip Erdoğan has said he feels confident Donald Trump will prevent sanctions from taking effect | Adem Altan/AFP via Getty Images US administration urged to punish Turkey over Russian missile shield ‘It’s a problem. There’s no question about it,’ says senior administration official.

WASHINGTON — Turkey on Friday received its first shipment of a Russian air defense system as calls grew for the United States to follow through on warnings to levy sanctions against the NATO ally and possibly eject Ankara from the new F-35 fighter jet program.

The Turkish Defense Ministry announced that the S-400 system was delivered to an air base near Ankara, according to multiple reports.

The Trump administration did not immediately take action, despite repeated warnings it will punish its longtime ally if it turned to Moscow for the high-tech anti-missile system, which is seen as a threat to the NATO alliance.

"We are aware of reports that Turkey has taken delivery of the S-400," a senior administration official told POLITICO in a statement late Friday. "As the President said at the G20 ahead of meeting with [Turkish President Tayyip] Erdoğan. It's a problem. There's no question about it.”

Acting Defense Secretary Mark Esper also spoke to his counterpart about the development on Friday, the Pentagon reported, declining to provide any details of what they discussed.

“Our position regarding the F-35 has not changed,” acting Defense Secretary Mark Esper told reporters earlier in the day before his call with Turkish Defense Minister Hulusi Akar. “There will be more to follow after that conversation.”

The Pentagon also delayed indefinitely a planned press briefing on the consequences of the S-400 delivery by Undersecretary of Defense for Acquisition and Sustainment Ellen Lord and Deputy Undersecretary of Defense for Policy David Trachtenberg.

The Pentagon and State Department have long maintained that it will expel Turkey from the U.S.-led F-35 fighter program if it took delivery of the S-400, which it fears would be able to map out vulnerabilities in the F-35’s stealth technology if the Turkish military operated both systems side by side.

The Pentagon has already taken incremental steps toward expelling Turkey from the fighter program. Last month, after the Pentagon learned that Turkey had begun sending troops to Russia for training on the S-400, the military set a timeline to stop training Turkish pilots to fly the F-35 by the end of July. It has also said said it would find other manufacturers to build F-35 parts now built in Turkey.

In a June letter, the Pentagon also said it would stop training Turkish pilots to fly the F-35 on July 31 and excluded Turkish representatives from a June F-35 chief executive officer roundtable.

“Turkey will not receive the F-35 if Turkey takes delivery of the S-400,” the letter said.

But Erdoğan has said he feels confident U.S. President Donald Trump will prevent sanctions from taking effect. After meeting with Trump at the G-20 summit last month, Erdoğan said he “never got the impression in meetings with Trump that there might be sanctions.”

Trump may not be able to stop Congress from sanctioning Turkey under the Countering America's Adversaries Through Sanctions Act -- and some lawmakers have proposed legislation that would block Turkey from receiving the F-35.

The top Democratic chairman and top Republican on the House Foreign Affairs Committee on Friday also called on the administration to follow through in its warnings.

“We have warned Turkey and President Erdogan time and time again that taking delivery of the Russian S-400 air and missile defense system would have serious consequences for the U.S.-Turkey relationship, including Turkey’s participation in the F-35 program," Rep. Elliot Engel of New York and Rep. Michael McCaul of Texas said in a statement. "We have warned them that obtaining the S-400 system would trigger sanctions. We have backed the Administration’s offer to sell the PATRIOT system to meet Turkey’s air and missile defense needs.

The bipartisan duo added: "That a NATO ally would choose to side with Russia and Vladimir Putin over the alliance and closer cooperation with the United States is hard to fathom. We call on the Department of State and the Department of Defense to terminate Turkey’s participation in the F-35 program and to sanction Turkish individuals doing business with the Russian defense sector, as required by law."

Other advocates for punishing the Erdoğan government, which has been roundly criticized for undermining democratic values in recent years, called on the Trump administration to follow Congress' lead.

Christians United for Israel, a pro-Israel organization, issued a statement Friday saying "Turkey continues its regression away from democratic values and towards pariah status. The country’s economy is paying the price, and now so too must its military. Turkey must be removed from the F-35 program,” said CUFI Action Fund Chairwoman Sandra Parker."

The Pentagon has iben urging Turkey to forego the S-400 and instead purchase the American-made Patriot air defense system made by Raytheon. Turkey has said it wants to have both the Russian and U.S. systems.

As the only Muslim majority member fo the NATO alliance, the U.S. and Turkey have been close allies. American combat planes flew missions against the Islamic State from Turkey’s Incirlik Air Base.

Congress has also been notified of more than $5 billion in U.S. arms sales to Turkey since 2009, according to a Congressional Research Service report from last year.