Washington and Ankara on Wednesday looked to brush aside differences that have strained relations for years, but were unable to report progress in resolving disagreements over Russia’s invasion of Ukraine and the expansion of NATO.

At Washington, Secretary Blinken and the visiting Turkish foreign minister, Mevlut Cavusoglu, sought to bridge those gaps, but there was no immediate sign that they had, even though both men lauded the partnership between their countries.

They played up cooperation on Ukraine, with Mr. Blinken in particular praising Turkey’s leadership in securing a deal with Russia for the transport of Ukrainian grain. Yet in brief remarks before their meeting, neither specifically mentioned their differences over the accession of Finland and Sweden to NATO, which the Turks have so far blocked despite strong support from the U.S. and other allies.

Turkey is demanding that the Swedes do more to rein in Kurdish groups that Ankara sees as a threat to its security before approving the alliance’s expansion.

“We are close allies and partners,” Mr.  Blinken said. “That doesn’t mean we don’t have differences, but when we have differences, precisely because we are allies and partners, we work through them in that spirit.”

Mr. Cavusoglu made no mention of Finland and Sweden in his comments, but did make a point of stressing the importance Turkey places on winning U.S. approval to buy advanced F-16 fighters, something the Biden administration supports but that faces significant congressional opposition.

The Turkish foreign minister called the F-16 deal a “significant topic” in U.S.-Turkey defense cooperation. “As we have said before, this is not only about Turkey but also for NATO and the United States as well. So we expect approval in line with our joint strategic interest,” he said.

In a joint statement released after the meeting, the two sides said they had “discussed strengthening the U.S.-Turkey defense partnership, including modernization of Turkey’s F-16 fleet,” as well as underscoring their mutual commitment to NATO’s expansion to qualified applicants.

Although the statement said the two sides were keen “to bolster NATO coordination and solidarity in the face of current threats and challenges,” it gave no indication that either of those issues had been resolved.

Mr. Cavusoglu’s visit, also eyed at Athens, was a rare one to Washington by a top Turkish official. President Biden’s administration has kept its distance from Turkey because of President Erdogan’s increasingly authoritarian direction and policies curbing rights and freedoms.

Positioned at the crossroads between East and West, Turkey is strategically important for Washington. As Mr. Blinken pointed out, Turkey was key to the agreement between Russia and Ukraine that allowed millions of tons of Ukrainian grain to be transported to world markets, averting a food crisis during the war.

The NATO allies, however, frequently find themselves at odds over a number of issues, with the biggest disputes centering on Turkey’s purchase of Russian-made missiles and support for Kurdish militants in Syria.

Turkey’s acquisition of the S-400 air defense system from Russia in 2017 led to sanctions and Turkey being removed from the development program for the next-generation F-35 fighter plane. After losing out on the F-35, Ankara is trying to restock its F-16 fleet. Mr. Cavusoglu said that Ankara’s request for F-16 fighter jets and Sweden and Finland’s NATO bids are unrelated. 

U.S. concern over Ankara’s cozy relationship with the Kremlin has been reinvigorated by the war in Ukraine. Despite Turkey’s ties with Moscow producing breakthroughs such as the grain deal and prisoner swaps, Washington is worried about sanctions-busting as Turkish-Russian trade levels have risen over the last year.

Also, Ankara’s feet-dragging over ratifying bids by Sweden and Finland to join NATO has added to friction between the allies. Turkey’s recent attempts at rapprochement with Syria after a decade of bitter enmity have caused another break with the U.S. 

Following a meeting of Syrian and Turkish defense ministers at Moscow last month, the U.S. Department of State reiterated its opposition to countries normalizing relations with Damascus.

The U.S. military has also warned that a threatened Turkish operation against the Kurdish YPG in northern Syria could destabilize the region and revive the Islamic State group.

Another thorn in Turkish-American relations has been Washington’s lifting last year of a decades-long arms embargo on the Republic of Cyprus. Mr. Cavusoglu recalled his displeasure with that decision in remarks to reporters following his meeting with Mr. Blinken: “Greek Cypriots will be able to buy weapons from the U.S. Against whom will it buy? Against the Turkish Cypriots, against Türkiye.”

Nevertheless, Mr. Cavusoglu invited Mr. Blinken to visit Turkey to attend the Antalya Diplomacy Forum in March.​​​​​​​