Britain’s home secretary criticized U.S. officials on Wednesday for leaking sensitive information about the inquiry into the extremist attack that killed 22 people at a Manchester concert arena.

Amber Rudd told Sky News that U.S. officials provided information to the news media that Britain preferred to keep confidential for reasons of operational security. Britain has raised its official terror threat to “critical” — meaning it is likely an attack is imminent — and is trying to uncover a suspected extremist network before it strikes again.

Rudd said the “element of surprise” in the police and security service measures could be compromised by information being released too quickly. Rudd said she had complained to U.S. officials to make sure the flow of information is staunched.

British officials hadn’t, for example, released the name of the bomber until it surfaced in the U.S. media based on leaks from U.S. officials briefed by their British counterparts. Other details also surfaced first because of leaks in Washington.

It comes at a time when European security officials have expressed concern about sharing intelligence with the U.S. after President Donald Trump discussed highly classified intelligence about the Islamic State group with senior Russian officials visiting the White House.

Rep. Adam Schiff of California, the ranking Democrat on the House intelligence committee, told reporters Wednesday he understands the concern about U.S. leaks possibly harming the U.K. police operation.

“If that’s something that we did, I think that’s a real problem,” he said. “If we gave up information that has interfered in any way with their investigation because it tipped off people in Britain — perhaps associates of this person that we identified as the bomber — then that’s a real problem and they have every right to be furious.”

He said, however, that even if U.S. intelligence sources shared vital information with the media, it likely would not affect the strong intelligence sharing relationship between the U.S. and Britain because it helps both countries.

A European security official said “having a U.S. leak when the situation has developed in the U.K. is nothing new.

“Historically, and nearly philosophically, the U.S. and U.K. intel services follow different paths,” the official said on condition of anonymity because he wasn’t authorized to speak about the investigation. “The U.S. have adopted a “zero risk” approach meaning that the U.S. services have a much shorter trigger when it comes to stop an ongoing operation. The U.K. services play it totally differently.”

This was highlighted in the 2006 trans-Atlantic liquid bomb plot. Americans wanted to pounce to quickly stop the plot whereas British authorities were trying to better determine the suspects’ capability and wider terror connections, according to two British officials who worked on the case at the time.

U.S. Homeland Security Department spokesman David Lapan declined to say Wednesday if suspected bomber in the Manchester attack, Salman Abedi, had been placed on the U.S. no-fly list. Under normal circumstances, he said, Abedi may have been able to travel to the United States because he was from Britain, a visa-waiver country, but he would have been subjected to a background check via the U.S. government’s Electronic System for Travel Authorization, or ESTA.

Lapan said the Homeland Security Department has shared some information about Abedi’s travel with the British government, but declined to offer specifics. Customs and Border Protection has access to a broad array of air travel information through the U.S. government’s National Targeting Center.