In a statement, foreign ministry spokesman Esmaeil Baqaei called the strikes a "continuation of the genocide and ethnic cleansing" in the Palestinian territories, and accused the United States of "direct responsibility" in the attack.

Israel carried out its heaviest attacks since the start of the ceasefire overnight, with the health ministry in Hamas-run Gaza reporting more than 400 people killed.

Baqaei warned of the "catastrophic consequences and implications of this situation on global peace and security".

Iran does not recognise Israel, which its officials refer to as the "Zionist regime", and Tehran has made support for the Palestinian cause a pillar of its foreign policy since the establishment of the Islamic Republic in 1979.

Tehran also supports the Palestinian militant group Hamas, with which Israel has been at war in Gaza since the group's October 7, 2023 attack on Israel.

Brokered by Qatar, Egypt and the United States, the ceasefire took effect on January 19, largely halting more than 15 months of fighting in the Palestinian territory triggered by the October 7 attack.

The first phase of the ceasefire ended in early March, and the two warring parties have been unable to agree on the next steps.