The U.S. ambassador to Russia on March 29 issued an unusual diplomatic statement refuting Russian government claims about information that the United States shared with Russia ahead of the terrorist attack last week on a concert hall outside Moscow that killed more than 140 people.

Ambassador Lynne Tracy said several Russian officials had “misrepresented and publicly dismissed” the usefulness of information passed on to Russian security services earlier this month related to threats from the Islamic State, which claimed responsibility for the attack soon after it was over.

In the statement, Tracy reiterated that the information shared with Russian authorities was in writing and was specific, timely, and credible.