Iran has called on Islamic and Arab countries to form a united front against Israel, as the West ramped up warnings against exploiting the volatile situation and touching off a regional conflict.
Tehran, which financially and militarily backs Hamas, has come under intense scrutiny since fighters of the Islamist group stormed across Israel's southern border at the weekend, shooting dead people in their homes and on the streets in an onslaught that claimed more than 1,200 lives.
Iran has insisted it was not involved in the attack but celebrated the assault as a "success".
As Israel responded to the deadly assault by pounding Hamas targets in Gaza, where officials reported 1,354 killed, Iranian President Ebrahim Raisi asked his Syrian counterpart Bashar al-Assad in a phone call to cooperate against Israel.
"All the Islamic and Arab countries... must reach serious convergence and cooperation on the path of stopping the crimes of the Zionist regime against the oppressed Palestinian nation," Raisi said in the call on Wednesday.
Accusing Israel of a "genocide of the Palestinians", Raisi said Iran will coordinate with Islamic countries "as soon as possible", the Iranian presidency website said on Thursday.
Tehran also offered to host an emergency meeting of the Organisation of Islamic Cooperation (OIC), which has 57 member states.
So far, no decision has been announced on this proposal.
But Iranian Foreign Minister Hossein Amir-Abdollahian is due to tour the region in the coming days, including Iraq on Thursday and Lebanon later to promote Tehran's initiatives.
He also spoke with his UAE counterpart Abdullah bin Zayed Al Nahyan on the phone, saying that "the continuation of attacks and the siege in Gaza are examples of collective punishment and systematic war crimes against humanity", according to a statement released by his ministry.
As a non-Arab country, Iran is excluded from several key organisations in the Middle East, such as the Arab League which met Wednesday in Cairo.
Unlike Iran, which does not recognise Israel and has made support for the Palestinian cause a centrepiece of its foreign policy since the 1979 Islamic Revolution, several Arab countries have been keen to improve relations with Israel.
Several Iranian dailies on Thursday splashed on their front pages images of the destruction caused by Israeli bombings in the impoverished Palestinian territory that over 2.4 million people call home.
However, they omitted mention of the more than 1,200 Israelis killed and 150 others taken across the border into captivity by the Islamist fighters.
While Western countries have not accused Tehran of direct involvement in the militants' attack, some have said the long-time support Iran has provided for Hamas enabled the group to carry out the assault.
"So far, we have no tangible evidence that Iran gave concrete and operational support to this cowardly attack," German Chancellor Olaf Scholz said Thursday.
"But it is clear to all of us that without Iranian support over the last few years, Hamas would not have been able to carry out these unprecedented attacks on Israeli territory," he added.
On Wednesday, US President Joe Biden warned Iran to "be careful" not to further fan the flames of conflict in the region.
Iran's Supreme Leader Ayatollah Ali Khamenei, who has the final say in major state policies, on Tuesday denied any Iranian involvement in the attack but reiterated the country's support for Palestinians.
On Thursday, Raisi described Israel's bombing of Gaza targets as a failure that is taking place only because Israel "cannot defeat the Palestinian youth and fighters".
The Iranian president has also spoken on the phone with Saudi Crown Prince Mohammed bin Salman.
So far, Iran's push has received a cautious response.
In the call with Raisi, Prince Mohammed said Saudi Arabia would work with regional and international partners to stop any escalation in the region.
Similar remarks have been made by Turkish President Recep Tayyip Erdogan, who, like Egypt, has offered to mediate for a ceasefire.