PALM BEACH, Fla. (AP) — The Latest on developments in the aftermath of U.S. airstrikes against Syria (all times EDT):

5:45 p.m.

Secretary of State Rex Tillerson said he sees no reason for retaliation from Russia for U.S. missile strikes on a Syrian air base.

Russia maintains a close political and military alliance with President Bashar Assad's government and has been accused of supporting its attacks against Syrians opposed to his rule — something Moscow adamantly denies

In an interview to air Sunday on CBS' "Face the Nation," Tillerson said Russians were not targeted by the strikes. He also said the top U.S. priority in the region hasn't changed and remained the defeat of Islamic State militants.

Tillerson says the Islamic State group is a threat not just to the U.S. but to stability in the region. He says that once the militant group is eliminated, the U.S. can turn to stabilizing Syria.

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5:35 p.m.

President Donald Trump has spoken by telephone with South Korea's leader to discuss Syria and North Korea.

The White House says that Trump spoke with South Korea's Acting President Hwang Kyo-Ahn about U.S. strikes in Syria in retaliation for a suspected chemical attack by President Bashar Assad's government on civilians.

The two leaders have agreed to stay in close contact regarding North Korea and other issues of mutual concern.

The call comes on the heels of Trump's two-day summit with China's President Xi Jinping during which North Korea's nuclear activities was at the forefront of their discussions.

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2:40 p.m.

The White House is circulating a letter President Donald Trump sent to the leaders of both houses of Congress explaining his decision to order military strikes on a Syrian air field.

In the letter, dated Saturday, Trump said he "acted in the vital national security and foreign policy interests of the United States, pursuant to my constitutional authority to conduct foreign relations" and as commander in chief.

Trump said he was sending the letter as part of his efforts "to keep the Congress fully informed, consistent with the War Powers Resolution."

Trump has received widespread support for the military action, taken to punish Syrian President Bashar Assad's government after the U.S. concluded he used chemical weapons against Syrian civilians.

But Trump also has faced some bipartisan pushback from lawmakers who have long insisted that presidents must seek congressional approval for acts of war.

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1:30 p.m.

The White House says President Donald Trump spoke with Saudi Arabia's king about Syria and he "reaffirmed strong Saudi support for the United States' military strike against the Sayrat airfield."

The statement says King Salman bin Abd al-Aziz al-Saud agreed it "was a necessary response" to the chemical weapons attack by Bashar Assad's government, which killed dozens of civilians in rebel-led northern Idlib.

The official Saudi Press Agency earlier reported that the king had complimented Trump in their telephone conversation for his "courageous decision."

Saudi Arabia is one of the most vehement opponents of Assad.