"An attack using two drones" targeted Ain al-Assad base in Anbar province on Tuesday evening, a police official said, speaking on condition of anonymity because he is not authorised to speak to the media.

"One drone was shot down outside the base by defence systems, and the second exploded inside the base without causing any injuries or damage," he added.

The attack comes amid escalating regional tensions fuelled by the war in Gaza between Washington's ally Israel and the Iranian-backed Palestinian Islamist movement Hamas.

Iran-backed armed groups in Iraq have largely halted similar attacks on US-backed troops in recent months, but have continued to threaten action should war break out between their ally Hezbollah in Lebanon and Israel.

A senior security official in Baghdad confirmed Tuesday's attack, saying he believed it was meant to "embarrass" the Iraqi government and pressure the international coalition to leave Iraq, a long-time demand of the Iran-backed groups.

The US military has some 2,500 troops deployed in Iraq and 900 in Syria with the international coalition.

The coalition was deployed to Iraq at the government's request in 2014 to help combat IS, which had taken over vast swathes of Iraq and neighbouring Syria.

The Islamic Resistance in Iraq, a loose alliance of Iran-backed groups, has carried out more than 175 rocket and drone strikes against US-led troops in Iraq and Syria.

It says the attacks are in solidarity with the Palestinians amid the ongoing war in Gaza, demanding an end to the Israeli offensive.

In April, rocket fire from northern Iraq targeted a base hosting the international coalition in Syria.

In late January, a drone strike launched by Iraqi armed groups killed three US soldiers in a base across the border in Jordan.

In retaliation, the US launched deadly strikes against pro-Iran factions in Iraq and Syria.

Baghdad has sought to defuse the tensions, engaging in talks with Washington to negotiate a timeline for the coalition's withdrawal.