WASHINGTON, Dec. 31 (Xinhua) -- U.S. President Donald Trump on Tuesday blamed Iran after furious Iraqi demonstrators mourning those killed in an earlier American attack in Iraq stormed the U.S. Embassy in Baghdad.

"Iran killed an American contractor, wounding many. We strongly responded, and always will. Now Iran is orchestrating an attack on the U.S. Embassy in Iraq. They will be held fully responsible," said Trump in a morning tweet.

"In addition, we expect Iraq to use its forces to protect the Embassy, and so notified!" Trump added.

On Tuesday, hundreds of demonstrators, participating in mourning for the Hashd Shaabi members killed by a U.S. attack in Iraq on Sunday, stormed the U.S. Embassy in Baghdad's Green Zone.

Some protesters smashed one of the gates and broke into the outer yards of the embassy, sparking a clash with the guards who fired tear gas canisters against the demonstrators, an official from the Iraqi Interior Ministry told Xinhua on condition of anonymity.

U.S. forces on Sunday attacked five locations in Iraq and Syria controlled by Iraq's paramilitary Kata'ib Hezbollah (KH), or Hezbollah Brigades, in response to recent attacks on U.S. forces in Iraq, triggering strong responses from Iraq and Syria, with Iran denying any role in the recent attacks on U.S. forces in Iraq.

Hashd Shaabi, an Iraqi state-sponsored umbrella organization, was formed by the KH and other Shia Iraqi paramilitary groups in 2014. It currently includes more than 40 militant groups.