Six Iranian nuclear scientists were killed, Iranian state media reported. Israel said it was working to intercept about 100 drones launched towards Israeli territory in retaliation.

Explosions were heard Friday morning in the Iranian capital, state TV reported, adding that Iran's air defense were at "100 percent operational capacity".

Indonesia has strongly condemned Israel's interception of the Madleen, a British-flagged humanitarian vessel bound for Gaza, calling the action a clear violation of international law and denouncing Israel’s blockade as collective punishment that risks causing mass starvation.

Commission chair Navi Pillay said in a statement accompanying the report: "We are seeing more and more indications that Israel is carrying out a concerted campaign to obliterate Palestinian life in Gaza."

The activist group departed Italy on June 1 aboard the Madleen carrying food and supplies for Gaza, whose entire population the UN has warned is at risk of famine.

Iranian state media reported on Saturday that Iranian intelligence agencies had obtained a large trove of sensitive Israeli documents. Khatib said these were related to Israel's nuclear facilities and its relations with the United States, Europe and other countries, and to its defensive capabilities. 

The British-flagged yacht Madleen, which is operated by the pro-Palestinian Freedom Flotilla Coalition (FFC), was aiming to deliver a symbolic amount of aid to Gaza later on Monday and raise international awareness of the humanitarian crisis there.

Aid distribution in Gaza was halted on Friday after the US and Israeli-backed Gaza Humanitarian Foundation (GHF) said overcrowding had made it unsafe to continue operations, in the latest disruption to its troubled relief effort.

Indonesia has expressed regret after the UNSC again failed to adopt a resolution on Gaza calling for a ceasefire and unhindered humanitarian access, which was stymied by a veto from key Israeli ally the United States.

Thousands of white-robed pilgrims recited Quranic verses from dawn on the 70-meter rocky rise near Mecca, where the Prophet Mohammed is believed to have given his last sermon.

The United States on Wednesday vetoed a draft UN Security Council resolution that demanded an "immediate, unconditional and permanent ceasefire" between Israel and Hamas militants in Gaza and unhindered aid access across the war-torn enclave.

In temperatures that are expected to climb to more than 40 degrees Celsius (104 degrees Fahrenheit), robed pilgrims will slowly circle the Kaaba, Islam's holiest site -- the black cubic structure at the centre of Mecca's Grand Mosque.

"It is unacceptable that Palestinians are risking their lives for food," Antonio Guterres said in a statement.

Israel recently eased its blockade and introduced a revamped aid mechanism in cooperation with a newly formed US-backed organization, bypassing the longstanding UN-led system.

Temperatures were forecast to exceed 40 degrees Celsius this week as one of the world's largest annual religious gatherings officially commences on Wednesday. 

"There is no humanitarian blockade. That is a blatant lie," Israel's foreign ministry said in a statement, defending its efforts to allow in aid. 

Iran carried out secret nuclear activities with material not declared to the UN nuclear watchdog at three locations that have long been under investigation, the watchdog said in a wide-ranging, confidential report to member states seen by Reuters.

The foreign ministers of several Arab countries, who had planned to visit the occupied West Bank this weekend, condemned on Saturday Israel's decision to block their trip.

The UN says that in the past 12 days it has only managed to transport some 200 truckloads of aid into Gaza, hindered by insecurity and Israeli access restrictions.

With international pressure mounting on Israel over the deepening hunger crisis in Gaza, Macron said action was needed "in the next few hours and days". 

They say it could deepen Western splits, not only within the already-divided European Union, but also with the United States, Israel's staunchest ally, and would need to be accompanied by other measures such as sanctions and trade bans if recognition were to be anything more than a symbolic gesture.

Israel accused the United Nations Wednesday of seeking to "block" Gaza aid distribution, as the global body said it was doing its utmost to gather the limited assistance greenlighted by Israel's authorities.

Indonesia has no formal ties with Israel and has consistently called for a two-state solution to the decades-long conflict.

Ramaphosa had hoped his talks with Trump in the White House on Wednesday would help reset relations with the United States that have nosedived since the US president took office in January.

It was not clear whether Israeli leaders have made a final decision and there was disagreement within the US government about whether they would ultimately decide to carry out strikes, CNN added, citing the officials.

Indonesia has condemned Israel’s continued attacks on the Gaza strip, including a recent assault targeting the Indonesia Hospital in Northern Gaza.

The top American diplomat blamed a resurgence of the Islamic State extremist group in areas outside of the transitional government's control, as well as Iran.