The Pentagon is considering sending several thousand additional troops to the Middle East to help deter Iranian aggression, amid reports of escalating violence in Iran and continued meddling by Tehran in Iraq, Syria and other parts of the region.

John Rood, defense undersecretary for policy, told senators Thursday that Defense Secretary Mark Esper “intends to make changes” to the number of troops deployed in the region. Other officials said options under consideration could send between 5,000 and 7,000 troops to the Middle East, but they all stressed there have been no final decisions. The officials spoke on condition of anonymity to discuss internal deliberations.

The troop deliberations follow several decisions since spring to beef up the U.S. presence in the Middle East because of a series of maritime attacks and bombings in Saudi Arabia that the U.S. and others have blamed on Iran.

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President Donald Trump has approved those increases, even though he also routinely insists that he is pulling U.S. troops out of the Middle East and withdrawing from what he calls “endless wars” against extremists. In October, Trump told his supporters that despite the sacrificing of U.S. lives in Iraq and other parts of the Middle East, the region is less safe and stable today. “The single greatest mistake our country made in its history,” he said, “was going into the quicksand of the Middle East.”

Asked about a possible troop increase, Trump told reporters Thursday that, “We'll announce whether we will or not. Certainly there might be a threat. And if there is a threat, it will be met very strongly. But we will be announcing what we may be doing — may or may not be doing.”

Military leaders have argued the U.S. needs to increase its presence in the region in order to deter Iran from conducting more and broader attacks. Rood provided no details to back up why the additional troops are needed but said the U.S. is concerned about recent intelligence indications suggesting an increased threat from Iran.

"The single greatest mistake our country made in its history was going into the quicksand of the Middle East." — President Donald Trump

Rood was asked several times about reports that 14,000 more troops could be sent to the region. He repeatedly said Esper hasn’t made a decision yet, but didn’t specifically confirm or deny the number, so his answers appeared only to confuse senators. Shortly after the hearing, Pentagon press secretary Alyssa Farah sent out a statement flatly denying the 14,000 number, saying Esper told the Senate committee chairman Thursday morning that “we are not considering sending 14,000 additional troops" to the region.

The troop discussions came as the Trump administration on Thursday accused Iranian security forces of killing more than 1,000 people in crackdowns against recent protests that have swept the country.

The estimated death toll is significantly higher than previous estimates from human rights groups and others, and the administration did not present documentary evidence to back up the claim. But Brian Hook, the U.S. special representative for Iran, told reporters the tally was based on a variety of reports coming out of Iran as well as intelligence analyses.

Speaking at the State Department, Hook said the U.S. had received and reviewed video of one specific incident of repression in the city of Mahshahr in which the Iranian Revolutionary Guards Corps had mowed down at least 100 protesters with machine-gun fire.

He said the video was one of tens of thousands of submissions the U.S. has gotten since Secretary of State Mike Pompeo appealed last month for Iranians to submit evidence of atrocities by the authorities in putting down the protests. In it, he said IRGC forces can be seen opening fire on protesters blocking a road and then surrounding those who fled to nearby marshlands where they were sprayed with bullets.

"We have seen reports of many hundreds more killed in and around Tehran. And, as the truth is trickling out of Iran, it appears the regime could have murdered over 1,000 Iranian citizens since the protests began." — Brian Hook, U.S. special representative for Iran

“In this one incident alone the regime murdered as many as 100 Iranians and possibly more,” Hook told reporters at the State Department. He did not display the video but said the actions it depicted corresponded to accounts of a brutal nationwide crackdown on the demonstrations, which started in response to gasoline price increases and rationing.

“We have seen reports of many hundreds more killed in and around Tehran," he said. "And, as the truth is trickling out of Iran, it appears the regime could have murdered over 1,000 Iranian citizens since the protests began.” The dead include 13- and 14-year-old children, he said.

Speaking at the White House, Trump said Iran had “killed hundreds and hundreds of people in a very short period of time” and called for international pressure to be applied. “They are killing protesters. They turned off their internet system. People aren’t hearing what’s going on,” he told reporters while hosting a lunch for the ambassadors of U.N. Security Council members.

Iran’s mission to the United Nations did not immediately respond to a request for comment, and there was no immediate comment on state media in Iran.