The prime minister criticized Israel and the U.S. for not consulting other nations or the U.N. before their attack on Iran.
There were students attending classes at the time that the school was destroyed. Some 175 people were killed by the attack on the girls’ elementary school.
President Trump also declined to rule out sending ground troops into Iran as the conflict spread into the Gulf countries and Lebanon and Israel exchanged strikes.
The number of U.S. service members killed in the first three days of the war grew as officials said the remains of two more troops had been recovered.
Smoke billows from at least four military ships that have burned for more than 24 hours, according to images released on Monday.
Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, acknowledged the possibility of an extended campaign, as the military announced that six U.S. service members had been killed so far.
Higher fuel prices and lower demand for international flights are expected to eat into airlines’ profits.
Fighting is spreading throughout the Middle East as Iran retaliates against a huge American-Israeli military campaign.
The government of Prime Minister Keir Starmer risks being dragged deeper into the conflict, after allowing the U.S. military to use British bases for “defensive” purposes.
How long prices remain high will depend on what the United States, Israel and Iran do next.