U.S. Secretary of Defense Mark Esper attends the meeting of the North Atlantic Council in Defence Ministers' session at the NATO headquarters in Brussels, Belgium, Oct. 25, 2019. (Xinhua/Zheng Huansong)

"This deployment is an appropriate and precautionary action taken in response to increased threat levels against U.S. personnel and facilities, such as we witnessed in Baghdad today," U.S. Secretary of Defense Mark Esper said.

WASHINGTON, Dec. 31 (Xinhua) -- U.S. Secretary of Defense Mark Esper said on Tuesday that the United States will deploy about 750 troops immediately to the Middle East, a move taken hours after demonstrators stormed the U.S. Embassy in Baghdad.

"Approximately 750 Soldiers will deploy to the region immediately and additional forces from the IRF (the Immediate Response Force) are prepared to deploy over the next several days," said the Pentagon chief in a series of tweets on Tuesday evening.

"This deployment is an appropriate and precautionary action taken in response to increased threat levels against U.S. personnel and facilities, such as we witnessed in Baghdad today," Esper added.

Protesters set fire to a guard room outside the U.S. embassy in Baghdad, Iraq on Dec. 31, 2019. (Xinhua/Khalil Dawood)

The Pentagon's decision came hours after hundreds of demonstrators, 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.

Many of the protesters, wearing Hashd Shaabi's military uniforms, rallied outside the embassy chanting slogans condemning airstrikes by the U.S. forces against Hashd Shaabi bases in Iraq.

The protest then turned violent as protesters set ablaze a guard tower and the outer gate of the embassy, an official from the Iraqi Interior Ministry told Xinhua on condition of anonymity.

U.S. President Trump blamed Iran for "orchestrating an attack" on the embassy in a Tuesday morning tweet. He later threatened in another tweet that Iran "will be held fully responsible for lives lost, or damage incurred, at any of our facilities."

"They will pay a very BIG PRICE! This is not a Warning, it is a Threat," the White House host added.

Also on Tuesday, Trump spoke over phone with Iraqi caretaker Prime Minister Adel Abdul Mahdi, emphasizing the need to protect United States personnel and facilities in Iraq, said the White House in a statement.

According to Esper, the troops to be deployed come from an infantry battalion from the IRF 82nd Airborne Division.

Israeli soldiers and military tanks are seen in the Israeli-occupied Golan Heights during a military drill on Dec. 30, 2019. The Israeli military was in a state of high alert in the Golan Heights, in readiness for possible retaliation by Iran after U.S. strikes on Kata'ib Hezbollah facilities in Iraq and Syria Sunday. (Photo by Gil Cohen Magen/Xinhua)

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. And Iran has denied 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 consists of more than 40 militant groups. ■