Kataib Hezbollah (the most secretive and most powerful of the Iraqi resistance groups) military spokesperson Jaafar al-Husseini expressed support as well:

In Iraq, Israel’s war on Palestine has regalvanized armed factions that formed in the wake of the 2003 U.S. invasion, an anti-occupation cause they see as directly linked to the Palestinian struggle for freedom. In just the last 24 hours, there have been several engagements between Iraqi militants and U.S. forces.

In his Baghdad office, Kataib Hezbollah military spokesperson Jaafar al-Husseini arrived for our meeting at the end of October in an upbeat mood that seemed at odds with the bloodshed that engulfed the region since October 7. “To the contrary, this is the easiest of times,” he explained. “This is a straightforward battle. Palestine is the fundamental issue.”

Kataib Hezbollah is the most secretive and most powerful of the Iraqi resistance groups. Although they’ve been partly incorporated into the government security apparatus as part of what Iraqi officials describe as a gradual demobilization — critics call it state capture at the hands of Iranian proxies — they relapse into violence during times of perceived Western meddling. The Pentagon’s recent decision to deploy aircraft carriers and personnel to the Middle East was taken as evidence of direct U.S. involvement in the Israel–Palestine conflict.

“America is a partner in this battle and in killing Palestinians, and therefore, they must pay the price,” al-Husseini said. “What is happening now in terms of targeting American bases is a natural response of the resistance fighters.”

America’s Unwavering Support for Israel Fuels Iran-Backed “Axis of Resistance”

Finally, the ordinary Iraqis expressed support:

An Iraqi boy carries a picture of Iran’s Supreme Leader Ayatollah Ali Khamenei during a protest in Baghdad, October 20, 2023, to express their support of the Palestinian people amid the ongoing battles between Israel and Palestinian groups. (AFP)

Will Israel-Hamas war in Gaza drag Iraq back into quagmire of conflict?

The Prime Minister of Iraq has supported Hamas after the attack on Ocrober 7, 2023:

On the day of Hamas’s attack, the Iraqi government issued a statement reaffirming Baghdad’s unwavering commitment to the Palestinian cause. It blamed Israel for the consequences of the attack as “a natural result of the systematic oppression they have been subjected to since ancient times at the hands of the Zionist [Israel] occupation authority.” It emphasized that Iraq stands with the Palestinian people in their pursuit of legitimate rights and unequivocally condemned any injustices and usurpations that obstruct the path to Palestinian statehood.

Iraq is at a crossroads. Will it choose its Shia militias or relations with the US? - Atlantic Council cites the X/Twitter Official Account of the Iraqi Prime Minister Media Office

The head of the Iraqi Shiite armed group of Asa’ib Ahl Al-Haq, Qais Al-Khazali, expressed support of Hamas as well.

In a rare visit, a Hamas delegation arrived in Baghdad on Oct. 27 at the invitation of Iraqi Shiite armed groups. [...] The Hamas delegation’s visit took place at the invitation of some Shiite armed groups loyal to the Iran-led ‘Axis of Resistance’—including Harakat Hezbollah Al-Nujaba and Kata’ib Hezbollah.

The Hamas members met with the former secretary-general of Kata’ib Hezbollah, Abdulaziz (Abu Fadak) Al-Muhammadawi, who currently serves as chief of staff of Iraq’s Popular Mobilization Units (PMU). The visiting Palestinians additionally met with the head of Asa’ib Ahl Al-Haq, Qais Al-Khazali. Of note, Khazali on Oct. 10 spoke with Haniyeh, expressing his “utmost readiness for any effort to liberate Al-Quds [Jerusalem] and support the Palestinian people.”

Inside story: The Hamas delegation’s rare visit to Iraq | Amwaj.media

The Prime Minister of Iraq has supported Hamas after the attack on October 7, 2023:

On the day of Hamas’s attack, the Iraqi government issued a statement reaffirming Baghdad’s unwavering commitment to the Palestinian cause. It blamed Israel for the consequences of the attack as “a natural result of the systematic oppression they have been subjected to since ancient times at the hands of the Zionist [Israel] occupation authority.” It emphasized that Iraq stands with the Palestinian people in their pursuit of legitimate rights and unequivocally condemned any injustices and usurpations that obstruct the path to Palestinian statehood.

Iraq is at a crossroads. Will it choose its Shia militias or relations with the US? - Atlantic Council

The above source quotes this post (translated from Arabic by Google):

@IraqiPMO

The operations carried out by the Palestinian people today are a natural result of the systematic oppression they have been subjected to since ancient times at the hands of the Zionist occupation authority, which has never adhered to international and UN resolutions. Therefore, we call on the international community to take action to put an end to the serious violations and restore the legitimate rights of the Palestinian people. Who still suffers from occupation, policies of racial discrimination, siege, transgression of sacred things, and violation of humanitarian values ​​and principles.

@IraqiPMO / The Official Account of the Iraqi Prime Minister Media Office, X/Twitter, 8:27 AM · Oct 7, 2023.

The head of the Iraqi Shiite armed group of Asa’ib Ahl Al-Haq, Qais Al-Khazali, expressed support of Hamas as well.

In a rare visit, a Hamas delegation arrived in Baghdad on Oct. 27 at the invitation of Iraqi Shiite armed groups. [...] The Hamas delegation’s visit took place at the invitation of some Shiite armed groups loyal to the Iran-led ‘Axis of Resistance’—including Harakat Hezbollah Al-Nujaba and Kata’ib Hezbollah.

The Hamas members met with the former secretary-general of Kata’ib Hezbollah, Abdulaziz (Abu Fadak) Al-Muhammadawi, who currently serves as chief of staff of Iraq’s Popular Mobilization Units (PMU). The visiting Palestinians additionally met with the head of Asa’ib Ahl Al-Haq, Qais Al-Khazali. Of note, Khazali on Oct. 10 spoke with Haniyeh, expressing his “utmost readiness for any effort to liberate Al-Quds [Jerusalem] and support the Palestinian people.”

Inside story: The Hamas delegation’s rare visit to Iraq | Amwaj.media