UK Home Secretary Amber Rudd slammed U.S. leaks on the investigation into the Manchester attack as “irritating” Wednesday and said she had made it clear that it “should not happen again.”

A string of details about Monday’s deadly attack at an Ariana Grande concert at Manchester Arena have emerged from U.S. law enforcement sources before being released by British police or officials.

“The British police have been very clear that they want to control the flow of information in order to protect operational integrity, the element of surprise,” Rudd told BBC Radio 4’s “Today” program.

“So it is irritating if it gets released from other sources and I have been very clear with our friends that that should not happen again.”

Asked if the leaks from U.S. officials had compromised the ongoing investigation, Rudd said she “wouldn’t go that far.”

But, she added, “I can say that they are perfectly clear about the situation and that it shouldn’t happen again.”

The UK terror threat level has been raised to critical for the first time in over a decade in the wake of the bombing, as more attacks could be imminent.

Meanwhile, investigators seek to track down any associates of the suspect, named as 22-year-old Salman Abedi.

Rudd earlier told Sky News that she expects the critical threat level to be temporary.

She also said the bomber was known “up to a point” by the intelligence services.

Abedi is believed to have died in the powerful blast, though he has not yet been formally identified by the coroner, Manchester police said.

The U.S. is one of Britain’s key intelligence partners. Both countries share sensitive information as part of the “Five Eyes” alliance, which also includes Canada, Australia and New Zealand.

Details were quick to emerge from the U.S. in the immediate aftermath of the bombing.

For example, U.S. officials told CNN that the attack appeared to be a suicide bombing and that a male at the scene had been identified as the probable suicide bomber.

The U.S. government has come under scrutiny over its handling of foreign intelligence in recent days following reports that U.S. President Donald Trump shared top secret information originating from Israel during a White House meeting with senior Russian officials. CNN