The U.S. is still holding out hope that Sweden will join NATO by July in spite of Turkey's apprehensions, Ambassador to Ankara Jeffry Flake said.
"We hope Sweden can become a member of NATO soon," Flake told CNBC's Dan Murphy Friday, adding that Sweden has taken a number of measures to address Turkey's security concerns.
"We fully expect and hope that by the time Vilnius comes ... that Sweden will be a member."
Earlier this week, Turkish President Recep Tayyip Erdogan had on Wednesday rebuffed mounting international pressure to ratify Sweden's NATO membership bid before the defense alliance convenes for the 2023 Vilnius summit of July 11-12.
Officials from Sweden, Turkey, Finland and NATO had convened in Ankara with hopes of easing Turkey's objections.
"Sweden has expectations. It doesn't mean that we will comply with them," Erdogan said, according to Turkish state-run outlet Anadolu. Turkey, Finland and Sweden had last year inked an agreement to on the sidelines of the NATO summit in Madrid, committing to address Turkey's security demands.
Ankara's objections are complex, but center mainly on Sweden's support for Kurdish groups that Turkey considers to be terrorists, and on weapons embargoes that both Sweden and Finland, along with other EU countries, put on Turkey for targeting Kurdish militias in Syria.
Erdogan also wants Sweden to crack down on protests against his government. For months, Sweden's capital has seen protests built up against Turkey, which at the start of the year led to the heavily criticised burning of the holy Muslim book Quran by some demonstrators.
"In order for us to comply with these expectations, first of all, Sweden must do its part," Erdogan said.
Prior to the recent elections in May, Turkey's presidential spokesperson in March said that Ankara has "left the door open" to Stockholm's bid to be a part of the military alliance "if it shows will and determination."
On Tuesday, U.S. President Joe Biden met with NATO's Secretary General Jens Stoltenberg, emphasizing their "shared desire to welcome Sweden to the Alliance as soon as possible," a White House statement said.
"Obviously, our relationship is grounded in NATO. I think it will continue to be so," Flake said of U.S.-Turkey relations, underscoring both parties' security and commercial partnership.
"On the commercial side, we['ve] got a healthy amount of balance trade, about 33 billion as of last year. That's increasing every year," he said.
The Turkish leader has previously criticized Flake for paying a visit to Kemal Kilicdaroglu, the presidential candidate of the opposition alliance that Erdogan beat in recent elections. Flake on Friday characterized his relationship with Erdogan as being "in a good place."
He added, "Sometimes it's a challenging relationship. That is true, but we have a good security and commercial and people relationship with Turkey."
—CNBC's Natasha Turak contributed to this article.