President Trump points to a family member as he makes cards for members of the military at a craft table during the 139th Easter Egg Roll at the White House on Monday. (Jabin Botsford/The Washington Post)

The White House on Tuesday defended a controversial congratulatory call by President Trump to Turkish President ­Recep Tayyip Erdogan after a referendum that greatly expanded the latter's powers, despite widespread concerns about the fairness of the vote.

Sarah Huckabee Sanders, the White House principal deputy press secretary, told reporters that Trump had no regrets about placing the call, saying it was “about developing the relationship.” Besides congratulating Erdogan, the “bigger point and priority” of Trump’s call on Monday was to talk about shared interests with a long-standing NATO ally.

“Look, the Middle East is a pretty rough neighborhood, and sometimes you have to get together to help them beat the bullies, like Syria,” Sanders said. “And that was something that certainly needed to be talked about.”

Sanders, who spoke to reporters aboard Air Force One as Trump traveled to and from an appearance in Wisconsin, also said that the president believes a review of election irregularities should continue and that he is not prejudging the outcome.

Asked by a reporter whether Trump would be able to work with an “undemocratic Turkey” on fighting terrorism, Sanders said the focus should not be on “whether or not it’s acceptable.”

“I think the president’s number-one job is to keep Americans safe,” Sanders said. “That is his priority. That has been the focal point during the campaign as well as since he took office. And if he needs to work with countries like Turkey and others to do that, I think that’s his priority, and that’s what his focus is.”

The referendum changed Turkey from a parliamentary democracy to one led by an executive president with strong central powers. The Turkish government said the measure passed by a slim margin, 51.3 percent to 48.7 percent, but opposition parties and international observers have raised questions about what they say are irregularities.

Even some leading Republicans have said they found the referendum results troubling.

“Turkey’s creeping authoritarianism continues,” House Foreign Affairs Committee Chairman Edward R. Royce (R-Calif.) said in a statement early Tuesday. “All who value democracy, pluralism and Turkey’s key role in the region should be concerned about the elimination of important checks and balances in the Turkish system.”

Royce said he was troubled by the reports of election irregularities and would “review the full body of facts when they are released in the days ahead.”

According to written accounts on Monday by both Trump and Erdogan, the two discussed during their call the U.S. missile strike on a Syrian air base in response to the April 4 chemical weapons attack on civilians in Idlib province. Trump thanked Erdogan for Turkey’s support of the retaliatory action. The leaders agreed that Syrian President Bashar al-Assad should be held accountable for the chemical attack, which killed at least 70 people, and they talked about the ongoing campaign to counter the Islamic State militant group.

In an interview broadcast Tuesday by CNN, Erdogan said Trump also congratulated him on the outcome of the referendum and was receptive to a suggestion that they have a face-to-face meeting soon.

“We agreed we would have that meeting in due course,” Erdogan said.

Trump’s written comments Monday night differed in tone from those of the State Department, which urged Turkey to respect the basic rights of its citizens and noted the election irregularities purportedly witnessed by monitors with the Organization for Security and Cooperation in Europe. The United States is a member of the OSCE.

A preliminary report by election observers said the referendum took place on an “unlevel playing field and the two sides of the campaign did not have equal opportunities.”

Erdogan’s opponents had been making the same charge for months. A government crackdown after a coup attempt in July went far beyond the coup plotters, leading to arrests of prominent opposition politicians and prosecutions of journalists critical of the government.

Carol Morello and Kareem Fahim contributed to this report.