Retired U.S. Army Lt. Gen. Michael T. Flynn arrives at the U.S. Capitol before the inauguration of President Trump. Flynn was invited to participate in Syria peace talks, sponsored by Russia, Turkey and Iran. (Pool photo by Saul Loeb/via European Pressphoto Agency)

The Trump administration will not send a delegation to next week’s Syrian peace talks, sponsored by Russia, Turkey and Iran, because of the “immediate demands of the transition,” the State Department said Saturday.

Russia’s ambassador to the United States had personally invited President Trump’s national security adviser, Michael T. Flynn, to the meeting, scheduled to begin Monday in Kazakhstan’s capital, Astana. The Obama administration was not invited.

“The United States is committed to a political resolution to the Syrian crisis through a Syrian-owned process, which can bring about a more representative, peaceful, and united Syria,” acting State Department spokesman Mark Toner said in a statement. It said that the U.S. ambassador to Kazakhstan would attend as an observer.

The invitation comes as the new administration is still formulating its policies toward a variety of issues, including the Syrian war, Russia and Iran, although Trump has promised changes from his predecessor. Secretary of state nominee Rex Tillerson has not been confirmed by the Senate, and no other senior diplomatic appointments have been finalized.

“Given our presidential inauguration and the immediate demands of the transition, a delegation from Washington will not be attending,” Toner’s statement said.

Representatives from the Syrian government and armed opposition groups seeking to overthrow it are scheduled to be there and, according to the sponsors, to hold face-to-face talks for the first time.

At the top of the agenda is an effort to solidify and continue a sputtering cease-fire the three sponsor nations negotiated last month. They hope to then begin preliminary talks on a negotiated political settlement to Syria’s civil war, now in its fifth year. A larger political meeting, to be held under United Nations auspices, is scheduled for Feb. 8 in Geneva.

The new effort follows a failed, year-long attempt by the United States and Russia — backing opposite sides of the conflict — to sustain a cease-fire and jump-start talks in Geneva. Since then, forces loyal to Syrian President Bashar al-Assad, with aid from Russia and Iran, have retaken the city of Aleppo from the rebels and extended their control of the country.

Turkey and the United States have both backed the rebels, although Trump has questioned the CIA program to arm and train them. But in recent months, Washington and Ankara have feuded over U.S. military support for Syrian Kurdish forces participating in the separate war against the Islamic State. When the Obama administration declined to provide air support for a Turkish military operation against the Islamic State inside Syria, Turkey turned to Russia.

The U.S.-Turkey breach has led to growing rapprochement between Turkey and Russia, whose warplanes this week flew joint bombing operations with Turkish counterparts in Syria.

In an interview Thursday in Washington, Turkish Foreign Minister Mevlut Cavusoglu rejected U.S. and European concerns that his government, a member of NATO and the U.S.-led coalition against the Islamic State, was “tilting” toward Russia.

“I think many NATO countries have better relations with Russia than Turkey has. . . . Despite the sanctions, many European countries are doing business with Russia,” Cavusoglu said. The United States and the European Union — of which Turkey is not a member — imposed sanctions against Russia for its military incursions in Ukraine on behalf of separatist fighters there, and for its annexation of Crimea.

Turkey has always “balanced” its relations with Russia, he said. “Have we changed our principled positions [opposing Russian activities] in Ukraine? No. On Crimea? No. How about the territorial integrity of Georgia?” which Russia invaded in 2008. “No. Many of our European friends are forgetting all of those issues, but Turkey never forgets.”

But in the absence of U.S. aid for its Syria operations, he said, Turkey had every right to appeal to Russia.

While Turkey also has “brotherly” relations with Iran, Cavusoglu said, he accused both Russia and Iran of failing to restrain their Syrian ally, Assad, from violating human rights as well as the cease-fire they helped negotiate.

It was Russia, and not the United States, that responded to Turkey’s call for assistance against the Islamic State, he said.

Attendance at the Astana talks would put the Trump administration at the same table as Iran, as well as Russia. During his campaign and post-election transition, Trump sharply criticized former president Barack Obama for alleged weakness toward Iran over its support for terrorism and weapons violations, as well as what he called the “bad” Iran nuclear deal.

Staffan de Mistura, the U.N. envoy to Syria, has said he will attend the talks in Kazakhstan. The Assad government is sending a delegation headed by its U.N. ambassador, Bashar Jaafari, an experienced negotiator.

Mohammad Alloush of the Jaish al-Islam (Army of Islam) rebel group — whose commander, Zahran Alloush, a cousin to Mohammad Alloush, was killed in a 2015 airstrike claimed by the Assad regime — will lead a “military delegation” of about eight people, backed by a group of political and legal advisers, Agence France-Presse reported.

A key rebel group, Ahrar al-Sham, said it would not attend because of government cease-fire violations but would support decisions taken by the other groups.