For an operation now dubbed "Swords of Iron," the Israel Defense Forces said Monday that it had struck 500 Hamas and Islamic Jihad targets in the Gaza Strip.

The attacks were carried out through the use of jets, helicopters and other aircraft, according to the IDF.

The IDF said seven of Hamas' command centers were struck in the mission.

-ABC News' Bruno Nota

An Iranian official at the UN denied that Iran had any involvement in Hamas' attack on Israel.

Israeli officials, including President Isaac Herzog, had claimed on Saturday that Iran helped coordinate the attacks on Israel.

On Sunday, however, Iran's Mission to the UN, denied the claims.

“We emphatically stand in unflinching support of Palestine; however, we are not involved in Palestine's response, as it is taken solely by Palestine itself.,” the Iranian Mission to the UN said in a statement late Sunday. “The resolute measures taken by Palestine constitute a wholly legitimate defense against seven decades of oppressive occupation and heinous crimes committed by the illegitimate Zionist regime.”

A U.S. official said Saturday it was "too early" to tell if Iran had involvement in the attacks.

"We are going to be looking at that very closely," a senior administration official said.

-ABC News' Kirit Radia

Israeli Defense Forces attacked the Gaza Strip early Monday morning local time, the IDF said in a series of posts on X, the platform formerly known as Twitter.

The IDF attacked a building where it said Hamas operatives were and several operational headquarters of the organization, the IDF said in the posts.

-ABC News’ Ellie Kaufman

An emergency meeting of the United Nations Security Council failed to condemn the Hamas attacks on Israel Sunday evening.

Deputy U.S. Ambassador the U.N. Robert Wood said the situation was "still fluid" and "very dangerous."

"What is important now is that the international community needs to show its solidarity with Israel. We have Israel's back fully as the United States, and the condemnation of Hamas needs to continue until they end this violent terrorist activity against the Israeli people," Wood said after the meeting.

-ABC News' Ellie Kaufman

The United States is warning against other countries from becoming involved in the Israel-Gaza conflict amid fears that it could spread into a wider war in the Middle East.

"This is not the moment for other parties who are hostile to Israel to seek advantage or to seek to exploit the attacks that have taken place," Jon Finer, deputy national security adviser to U.S. President Joe Biden, Monday on "Good Morning America."

"That is part of why the United States has moved the Carrier Strike Group to the eastern Mediterranean to send a strong and unmistakeable signal that no one else should get involved in this," he added. "We'll see how things unfold in the course of the coming days."

Finer also emphasized that the U.S. believes "Israel has every right to defend itself full-stop."

"Israel will ultimately make the decisions about how it chooses to go about and conduct that defense," he said. "We are offering support in a number of ways."

Finer noted that "more U.S. steps to show support and solidarity for Israel" can be expected.

"The U.S. is going to offer support at every level for Israel's defense and we are working through details those details with our intelligence professionals, our military and our diplomats," he added. "We are in daily -- in fact, many times a day -- contact with Israeli counterparts to see what they need and offer it."

The U.S. "strongly suspect[s] that there will be American citizens among those killed" in the ongoing conflict, according to Finer.

"We are looking obviously very intensively into whether there were any Americans were among those who have been abducted and brought to Gaza. This is still ongoing," he said. "There is still fighting inside Israel as we speak and there is a bit of fog of war in terms of the ability to gather specific information. And so, we will have much more to say about this at the right time."

When asked for comment on a recent report by The Wall Street Journal that Iran was behind Hamas' latest attack on Israel, Finer responded: "We have no direct information to confirm that report. We've obviously seen it, we're looking into it, but we do not have the ability to corroborate it at this time."

"What we can be quite clear about is that Iran is broadly complicit in these attacks for having supported Hamas going back decades -- for having provided financial support, for having provided training, for having provided weapons to Hamas," he added. "What we don't have is direct information that shows Iranian involvement in ordering or planning the attacks that took place over the last couple days. It's something that we’re going to keep looking at closely."