WASHINGTON (NewsNation) — According to the Pentagon, Iranian-backed militants have launched 64 attacks on bases and facilities housing U.S. personnel in Iraq and Syria since Oct. 17.

Of those, 30 have been in Iraq and 34 in Syria.

The U.S. has about 2,000 troops in Iraq, under an agreement with the Baghdad government, and about 900 in Syria, mainly to counter the Islamic State group but also using the al-Tanf garrison farther south to keep tabs on Iranian proxies moving weapons across the border.

The latest jump in attacks began 10 days after Hamas’ Oct. 7 incursion into Israel, where at least 1,200 people were killed. Israel’s blistering military response has killed thousands of civilians trapped in Gaza and fueled threats of retaliation by a range of Iran-backed groups, including Hezbollah in Lebanon, Yemen-based Houthis and militants in Iraq and Syria.

Those threats escalated after an Oct. 17 blast at a Gaza hospital killed hundreds of civilians. Hamas blamed Israel for the explosion, but Israel has denied it, and both Israeli and U.S. officials have blamed it on a missile misfire by Islamic Jihad.

Since the Oct. 7 Hamas attack, the Biden administration has moved warships, fighter jets, air defense systems and more troops into the Middle East in a campaign to discourage militant groups from widening the conflict.

But the U.S. military response to the attacks on its forces has been minimal. On Oct. 27, U.S. fighter jets struck two weapons and ammunition storage sites in eastern Syria near Boukamal that were used by Iran’s Islamic Revolutionary Guard Corps and Iranian-backed groups.

On Nov. 8, fighter jets dropped bombs on an IRGC weapons storage facility near Maysulun in Deir el-Zour. And on Nov. 12, U.S. airstrikes targeted a training facility and a safe house in the Bulbul district of Mayadin. U.S. officials said IRGC-related personnel were there and likely struck but provided no details.

There are concerns within the Biden administration that more substantial retaliation could escalate the violence and trigger more deadly attacks. The Pentagon says the strikes have degraded the group’s military stockpiles and made the sites unusable.

But critics argue that the U.S. response pales in comparison with the 64 attacks and American injuries, and — more importantly — has obviously failed to deter the groups.

The Associated Press contributed to this report.