By Jasper Ward and Nidal al-Mughrabi

WASHINGTON/CAIRO (Reuters) - Iran's foreign minister on Friday said Tehran was investigating an overnight attack on Iran, adding that so far a link to Israel had not been proven as he downplayed the strike.

Iranian Foreign Minister Hossein Amirabdollahian told NBC News the drones took off from inside Iran and flew for a few hundred meters before being downed.

"They're ... more like toys that our children play with, not drones," Amirabdollahian said.

"It has not been proved to us that there is a connection between these and Israel," he said, adding that Iran was investigating the matter but that media reports were not accurate, according to Tehran's information.

Iranian media and officials described a small number of explosions, which they said resulted from air defenses hitting three drones over Isfahan in central Iran in the early hours of Friday. They referred to the incident as an attack by "infiltrators", rather than by Israel, obviating the need for retaliation.

Amirabdollahian warned that if Israel retaliated and acted against the interests of Iran, Tehran's next response would be immediate and at maximum level.

"But if not, then we are done. We are concluded," he said.

The attack appeared to target an Iranian Air Force base near the city of Isfahan, deep inside the country, but without striking any strategic sites or causing major damage.

Israel has said nothing about the incident. U.S. Secretary of State Antony Blinken said the United States had not been involved in any offensive operations, while the White House said it had no comment.

CALIBRATED RETALIATION

Israel had said it would retaliate after a strike on April 13, the first ever direct attack on Israel by Iran, which caused no deaths after Israel and its allies shot down hundreds of missiles and drones.

Tehran launched those attacks in response to a presumed Israeli airstrike on April 1 that destroyed a building in Iran's embassy compound in Damascus and killed several Iranian officers including a top general.

Allies including the U.S. had pressed all week to ensure any further retaliation would be calibrated not to provoke more escalation, and Western countries tightened sanctions on Iran to mollify Israel.

There was no word from Israel on Friday as to whether further action might be planned. Apart from direct strikes on Iranian territory, it has other ways of attacking, including cyber attacks and strikes on Iranian proxies elsewhere.

Violence between Israel and Iranian proxies across the Middle East has intensified throughout six months of bloodshed in Gaza, raising fears the longstanding foes' shadow war could spiral into a direct conflict.

Israel's assault on Gaza began after Hamas Islamists attacked Israel on Oct. 7, killing 1,200, according to Israeli tallies. Israel's military offensive has killed 34,000 Palestinians in Gaza, according to the Gazan health ministry.

As night fell on Friday, Israeli planes and tanks pounded several areas across the Gaza Strip, with air strikes hitting areas of Rafah where over half of Gaza's 2.3 million people are sheltering, according to residents, Hamas media and officials at the Hamas-run Gaza health ministry.

One strike hit two apartments in a residential building in the city, killing nine people, including four children, and wounding several others, health officials said.

Air strikes also destroyed at least five houses in the Al-Nuseirat refugee camp in central Gaza, residents and Hamas media said.

"They (Israeli security) phoned some residents and ordered them to evacuate their houses before planes bombed some buildings nearby," Abu Omar, a resident of Al-Nuseirat, told Reuters via a chat app.

"Soon as we ran away explosions shook the ground," he added.

Israel's government did not immediately reply to a request for comment.