Iranian President Masoud Pezeshkian said on Sunday his country would stand firm following Israel's attack on Iran.

"Definitely the free people will not back off in the face of this criminal, blood-thirsty regime. We have always defended the rights of our people and will continue to do so," Pezeshkian told cabinet members, according to The Associated Press.

Earlier, Iranian state TV reported that Pezeshkian said Iran would respond to Israel "appropriately.”

Israel attacked military targets in Iran on Saturday in retaliation for the barrage of ballistic missiles Iran fired on Israel earlier this month, marking the first time the IDF has openly attacked Iran.

Pezeshkian also warned tensions will escalate if Israel’s aggressions and crimes continue.

-ABC News' Ellie Kaufman

The U.N. Security Council will meet Monday at Iran's request after Israel’s retaliatory attack against the country, a spokesperson for the Israeli Ambassador to the U.N. confirmed to ABC News.

The Iranian Ministry of Foreign Affairs called Israel’s retaliatory attack a "serious violation of the sovereignty and territorial integrity of the Islamic Republic of Iran and a flagrant breach of international law," in a letter requesting the U.N. Security Council meeting.

The letter from Iran's Ministry of Foreign Affairs was sent to the UNSC’s current president and U.N. Secretary General António Guterres.

-ABC News' Ellie Kaufman

An Israeli citizen was at the wheel of a truck that rammed a bus stop Sunday morning in Tel Aviv, Israel, killing one person and injuring about 40 others in what police said is being investigated "with an emphasis on the suspicion that this is a terror attack."

The incident unfolded at about 10 a.m. near the Glilot military base, police said.

"During a situational assessment at the scene conducted by Israel Police Commissioner Daniel Levy together with Tel Aviv District Commander Dep. Comm. Chaim Sargrof, it was revealed that the driver, an Israeli citizen, was neutralized in the truck’s cabin by gunfire from a civilian present at the scene," according to the police statement.

-ABC News' Jordana Miller

At least nine people were killed and 20 others were injured in an Israeli airstrike Sunday on the Asmaa School in the Shati refugee camp in western Gaza City, according to the Hamas-run Civil Defense in Gaza.

The Israel Defense Forces (IDF) did not immediately respond to an ABC News request for comment on the reported attack.

The U.N.-run Asmaa School has previously been hit by Israeli airstrikes, including one eight days ago that killed at least seven people, according to Civil Defense.

Video from Reuters showed crowds gathered near the school, where bodies appeared to be scattered and rescue crews searched the rubble for survivors.

-ABC News' Victoria Beaule

Documents purporting to show classified U.S. intelligence-gathering on Israel's preparations for a possible retaliatory strike against Iran appeared on social media platforms late last week.

The impact of the circulation of these documents on current and future planning by the Israeli military is unclear at this time.

U.S. officials declined to comment on the situation when reached by ABC News. However, a law enforcement source on Sunday confirmed with ABC News that there is an investigation underway.

Markings on the documents indicate that they would have originated from the National Geospatial-Intelligence Agency, which collects, analyzes and distributes intelligence gleaned from satellite and aerial imagery.

If the documents are authentic, it would indicate a major intelligence breach.

According to Mick Mulroy, an ABC News national security and defense contributor, who served as the deputy assistant secretary of defense for the Middle East: "The future coordination between the U.S. and Israel could be challenged, as well."

The Department of Defense, Federal Bureau of Investigation and a spokesperson for the Office of the Director of National Intelligence all declined to comment when contacted by ABC News.

House Speaker Mike Johnson appeared on CNN Sunday and acknowledged that there is an investigation underway into the possible intelligence leak, adding, "We're following it closely."

-ABC News' T. Michelle Murphy