Washington (MEE– The United States will send about 1,000 additional troops to the Middle East in response to White House claims that Iran attacked two oil tankers in the Gulf of Oman last week, Defense Secretary Patrick Shanahan said.

“The recent Iranian attacks validate the reliable, credible intelligence we have received on hostile behavior by Iranian forces and their proxy groups that threaten United States personnel and interests across the region,” Shanahan said in a statement on Monday, Reuters news agency reported.

The Pentagon last week released a video showing what it said was an Iranian boat that pulled up alongside one of the stricken tankers and removed a mine attached to its hull.

Adam Schiff, head of the House Intelligence Committee and a leading Democratic critic of the administration, said the evidence of Iranian involvement “is very strong and compelling”.

Related: The White House PR Campaign Against Iran Has Been Defeated

Iranian foreign minister Javad Zarif last week denied the US charges and said they were made without “a shred of factual or circumstantial evidence”.

A third of the world’s seaborne oil supply passes through the Strait of Hormuz, a narrow channel bordered to the north by Iran.

Tensions between Washington and Tehran have increased since President Donald Trump withdrew the United States from a 2015 international nuclear deal with Iran last year.

Trump’s administration has reimposed sanctions on several key Iranian industries as it seeks to end Iran’s international sales of crude oil and strangle its economy.

Last month, the US deployed a carrier strike group and bombers to the region and had earlier announced plans to deploy 1,500 troops to the Middle East, prompting fears of a conflict.

Related: Oil Tanker Attacks: Russia Warns Against Blaming Iran

Iran, for its part, announced earlier on Monday that it intends to break the uranium stockpile limit set under the nuclear deal agreed with world powers from 27 June.

“Today the countdown to pass the 300kg reserve of enriched uranium has started and in 10 days time we will pass this limit,” Iranian atomic energy organization spokesman Behrouz Kamalvandi said on Iran’s national broadcaster.

“This is based on the Articles 26 and 36 of the [nuclear deal], and will be reversed once other parties live up to their commitments,” he added, speaking from the Arak nuclear plant southwest of Tehran.

This post was originally written for and published by Middle East Eye and appears here with permission.