President Donald Trump’s Secret Service was silently beefed up after Charlie Kirk‘s assassination, reviving safety fears for the president and his allies.

Amid the shock of the death of Kirk, Trump’s close ally and friend, the president and his allies’ security details and precautionary measures were expanded, a senior White House official told the Wall Street Journal. A 9/11 commemoration ceremony at the Defense Department, where Trump delivered a speech, was moved to a more secure location, the official said, while the law enforcement presence at the Thursday Yankees game was expanded.