Donald Trump commented Monday on the explosion at a Russian metro station that killed multiple people.

As the president welcomed Egyptian President Abdel Fattah el-Sisi to the State Dining Room of the White House, he was asked by a reporter to comment on the explosion at a St. Petersburg subway station, which killed at least 10 people and injured dozens more.

“Terrible,” Trump said. “Terrible thing. Happening all over the world. Absolutely a terrible thing.”

After the first explosion went off, the city shut down its metro system and defused a second bomb at another station shortly afterward.

President Vladimir Putin said all causes are being investigated, including terrorism.