The top diplomats also discussed the US killing in Baghdad of top Iranian commander General Qasem Soleimani in January, and bilateral cooperation between the two neighbours.

Zarif, in an English-language tweet, said they discussed "attacks on Iranian diplomatic premises" in Iraq, adding that he had underlined to Hussein the "imperative of protection of diplomatic posts".

They also "reviewed practical steps to further enhance bilateral cooperation" and "discussed (the) US terrorist murder of our hero General Soleimani".

His comments come more than a week after three separate attacks targeted Western diplomatic or military installations in Iraq.

On September 15, an improvised explosive device targeted a British embassy vehicle just outside the high-security Green Zone in Baghdad that houses diplomatic missions.

Hours before that, two Katyusha rockets targeted the US embassy in the Green Zone, an Iraqi security source said at the time.

And the previous day two explosive devices targeted a US-led coalition equipment convoy, the Iraqi military had said.

Iraqi intelligence sources have blamed similar attacks on a small group of Iran-backed paramilitary factions.

Iranian diplomatic missions in Iraq were attacked last year amid anti-government protests and charges that Tehran is propping up the government in Baghdad.

The last attack occurred in November 2019 when anti-government demonstrators torched the Iranian consulate in the Iraqi holy city of Najaf.

Soleimani was killed in January in an American drone air strike near Baghdad airport, alongside top Iraqi commander Abu Mahdi al-Muhandis.

Days later, Iran launched a volley of missiles at Iraqi bases housing US and other coalition troops.

The Zarif-Hussein talks come three days after the US granted Iraq a 60-day extension to a sanctions waiver, allowing it to import Iranian gas for its crippled power grids.

The US blacklisted Iran's energy industry in late 2018, but has since granted its ally Baghdad a series of temporary waivers to stave off country-wide blackouts.

Iranian President Hassan Rouhani also met Hussein and reiterated Iran's opposition to the presence of foreign troops in the region.

"The presence of US armed forces in the region, whether in Iraq, Afghanistan, or southern Persian Gulf countries is detrimental to regional security and stability," Rouhani said.

It was the duty of "every country where Americans are present" to try to remove them, he added.

Following Soleimani's killing, Iraq's parliament called on the government to end the presence of foreign troops in Iraq.

"We consider what the Iraqi parliament and representatives of the people of this country have approved in this regard is respected by the Iraqi people and has our support," Rouhani said.

In early September, the US announced a sharp cut to troop numbers in Iraq from 5,200 military personnel to just 3,000.