Canada's top military commander has formally hit the pause button on operations in Iraq as fallout from the U.S. targeted killing of Iranian Gen. Qassem Soleimani in Baghdad continues.

The chief of the defence staff, Gen. Jonathan Vance, released a letter on Twitter Tuesday that says Canadian operations in both the NATO training mission and the U.S.-led coalition hunting the remnants of the Islamic State, known as Operation Impact, have been suspended.

The letter was addressed to family members of those serving overseas.

Vance said all necessary measures to protect forces have been taken and security for the troops is constantly being evaluated.

"The situation in Iraq is complex and it is best to pause our work there in order to fully concentrate our attention and efforts towards the safety and security of our personnel while the situation develops," Vance wrote. "Simply put, we're doing this to ensure their safety and security."

A letter from General Jonathan Vance, Chief of the Defence Staff, to Canadians about our deployed personnel in the Middle East. <a href="https://twitter.com/hashtag/OpIMPACT?src=hash&ref_src=twsrc%5Etfw">#OpIMPACT</a> <a href="https://t.co/Y0IdmZdo9f">pic.twitter.com/Y0IdmZdo9f</a> —@CanadianForces

The U.S., similarly, said a few days ago that it was also pausing anti-ISIS operations in order to concentrate on defending bases and American facilities.

Speaking Monday on CBC News Network's Power & Politics, Defence Minister Harjit Sajjan said some non-essential personnel had been moved out of Iraq.

Vance's letter confirmed the move and said they will be relocated to Kuwait and also indicated that the leave plans of some personnel may be interrupted.

Canada has about 500 troops in Iraq performing the two separate missions.

The Iraqi Parliament voted last weekend on a non-binding resolution calling on the government to expel all foreign troops from the country after the killing Soleimani and several others in a U.S. drone strike last weekend. It still has to be signed by the caretaker-prime minister, Adel Abdul-Mahdi, but there are questions about whether he has the legal authority to do so.

On Monday, Abdul-Mahdi called for U.S. co-operation to prevent war with Iran and to work the interim government to bring about the exit of American troops from his country.

U.S. Defence Secretary Mark Esper told reporters in Washington that the U.S. is not seeking war, but he conceded he expects Iran to retaliate. He called on Tehran to "de-escalate" and warned that the Americans would defend not only their interests, but also their allies in the region.

U.S Defense Secretary Mark Esper says that the United States is not seeking war with Iran, but will defend their allies and partners should they face retaliation from Iran. 0:49

Canada's former military representative at NATO, retired vice-admiral Bob Davidson, said the Iranians may have political reasons to avoid targeting the Canadian-led alliance training mission in Baghdad.

That mission involves a number of European troops, whose countries still back a nuclear deal, which U.S. President Donald Trump walked away from last year. The agreement, which was made under former president Barack Obama, tried to limit Iran's nuclear program. But with Washington out, Tehran has been walking back its commitment.

European countries are mulling whether to reimpose sanctions or opt for the agreement's dispute resolution mechanism.

'Rather foolish'

The Iranians may not be eager to anger those countries, such as Germany, with a direct attack on NATO forces, Davidson said.

"If you think about the efforts of France and the effort which has been applied to finding solutions, I think for the Iranians, slamming that door by attacking NATO forces is rather foolish," he said.

"The real challenge is whether NATO forces are in close proximity to U.S. forces. And are the actors on the ground sufficiently sophisticated enough to know the difference between the targets?"

Iran's use of proxy forces, such as Iraqi militias and Hezbollah in Lebanon, also introduce a degree of uncertainty.

"There are a lot of wild cards that could come out as well, so you cannot discount the threat," he said.

Trudeau talks with foreign leaders

Since returning to Ottawa over the weekend, Prime Minister Justin Trudeau has worked the phones with other world leaders, including one call on Monday with Charles Michel, president of the European Council.

The two leaders "expressed their shared support for preservation of the Joint Comprehensive Plan of Action (JCPOA)," the nuclear deal with Iran.

It is a signal that Canada is sticking close with its European allies. Trudeau also spoke on Tuesday with German Chancellor Angela Merkel and Jordan's King Abdullah II.

Trudeau's former foreign policy adviser, Roland Paris, says Canada has an interest in "sustaining" the anti-ISIS coalition.

"We saw what happened the last time when American troops left Iraq, within two years ISIS had overrun the country and that posed a threat not just to the region but to us as well," he said.

Paris says that Trudeau's top preoccupation when speaking with other world leaders is the security and safety of Canadians in the region, followed by maintaining the integrity of the anti-ISIS training mission itself.