Seven oil tankers caught fire or were damaged in the Strait of Hormuz overnight after being hit by Iran or striking naval mines, Tehran said Thursday, a markedly high number as tensions wind upward over concerns about a return to all-out war.

With days before Israel’s close elections in which Prime Minister Benjamin Netanyahu could lose power, and ahead of next month’s U.S. midterm elections in which war-linked high prices have sparked voter anger, there are concerns that U.S.- Israeli attacks on Iran could resume.

Iranian state television reported the claims about the latest attacks on ships, citing the Revolutionary Guard Corps navy, which again threatened to strike U.S. military bases in the region if the U.S. keeps helping to guide commercial ships through the strait.

The report did not mention casualties. A British military monitor, the United Kingdom Maritime Trade Operations, did not report the attacks, but monitors in recent days have noted reluctance by some shippers to report incidents.…