Newly released documents shed light on how the Canadian government responded following an attack on the U.S. consulate in Benghazi, Libya, last summer.

The heavily redacted documents, obtained by CBC News under federal Access to Information laws, show officials in Ottawa reacted within hours of confirmation of the Sept. 11, 2012 attack on the American mission in Benghazi.

Attackers armed with rifles and rocket-propelled grenades had stormed the U.S. consulate and set it on fire, killing two diplomats, including Christopher Stevens, the U.S. ambassador to Libya. Two more officials were killed in a related attack on a second U.S. facility in the city.

The attack on the mission in Benghazi started at 9:42 p.m. local time on Sept. 11, according to a timeline released by the Pentagon. That's 3:42 p.m. ET.

In an email sent just before 9 a.m. ET on Sept. 12, the morning after the attack, a secret briefing note from the Department of Foreign Affairs' regional security abroad unit outlined safety measures for the Canadian embassy in Tripoli, Libya's capital. The measures are blacked out in the version released publicly.

Another briefing note, marked secret and dated Sept. 12 at 12:30 p.m., says the department "disseminated a security message to inform all missions of the threat and request all missions review their security posture and ensure readiness," and that the regional security abroad unit had been in touch with the missions in Tripoli and Cairo, Egypt, and had produced briefing notes on events in Benghazi and Cairo.

A spokesman for Foreign Affairs Minister John Baird wouldn't say what time the first messages went out, citing security concerns, but allowed that they went out "early morning" on Sept. 12.

"By midday on the 12th, the two missions in question [Tripoli and Cairo] had updated security instructions relevant to the Canadian context at the time," Chris Day said in an email to CBC News.

The documents show the also department arranged by early afternoon on Sept. 12 a conference call for heads of mission in the Middle East and North Africa.

'Reacted thoroughly and rapidly'

NDP international co-operation critic Hélène Laverdière, who served as a Canadian diplomat in Chile and Senegal, says it sounds like officials "reacted thoroughly and rapidly."

"There was probably a quick reaction on the ground, because you have what happens in Ottawa, but the people on the ground, they're also aware of what's happening, and they're also talking with colleagues from other missions and sometimes exchanging experience about security measures and things like that," she said.

Laverdière says there was a minor earthquake when she was posted in Chile, and within 10 minutes, colleagues in Ottawa were checking in on the Canadians in Santiago.

"Quite sincerely, my impression … is that the department reacted rather quickly [to what happened in Benghazi] and I can tell you from my experience, all along, it's always a priority: security of the mission, security of the information, but above all, security of the people."

Canada temporarily closed its embassies in Cairo and Tripoli from Sept. 13-16, and Khartoum, in Sudan, from Sept. 14-17, after outbursts of unrest following the release of an amateur American film called The Innocence of Muslims, which ridicules the prophet Mohammed.

"We take the safety of our personnel and our missions overseas very seriously," Day said. "We are always monitoring events closely and taking appropriate security measures."

The U.S. embassy in Cairo also saw a major protest the day of the attack on the consulate in Benghazi, with demonstrators climbing the walls of the mission and tearing down the American flag.

The attack in Benghazi is now thought by U.S. officials to have been a planned attack by militants linked to al-Qaeda.

'Attack on diplomacy'

The embassy in Libya is staffed by five Canadians. Canada had no diplomats in Benghazi at the time of the attack, Baird said in September.

Children and spouses aren't allowed to follow officials on posting in Tripoli, one of the post-attack memos says, and Canada-based staff must take a hostile environment training course before being posted there. They receive "thorough" security briefings on arrival and throughout their time in Libya, it says.

Stevens was the first U.S. diplomat killed in a violent assault since 1979.

"It's an attack on diplomacy, and obviously we continually look at the safety and security environments for Canadian personnel," Baird told reporters on Sept. 12. He was travelling in India at the time.

"We're obviously not present in Benghazi. But as you would expect, we'll re-evaluate the environment, as we regularly do, for our personnel in Tripoli. Obviously, we understood that [the country] wasn't going to go from Moammar Gadhafi to Thomas Jefferson overnight, and we continue to put our hope in the actions to bring civil society and pluralism and democracy to the people of Libya."

Baird also said the government was reviewing embassy security around the world.

"Obviously diplomats don't sign up to be soldiers, and their safety and security is a high priority. We've made major strides over the past 10 years of the department to meet these goals. There are areas where there is room for improvement and obviously we are seized with the importance of this."