Editor's note: Imtiaz Gul is head of the independent Center for Research and Security Studies, and author of the book "The Most Dangerous Place," as well as "Pakistan: Before and After Osama." Follow @vogul1960 on Twitter. The views expressed in this commentary are solely those of Imtiaz Gul.
Islamabad, Pakistan (CNN) -- The brazen terrorist assault on Pakistan's largest Karachi Airport that began near midnight Sunday left almost everybody stunned.
It was the Pakistani Taliban's biggest strike on state security apparatus -- in terms of human casualties -- and is a reminder of the massive security challenge that comes from affiliates of al Qaeda holed up in the mountainous Pakistan-Afghanistan border terrain.
Of the 28 dead, 10 were attackers who were killed during a firefight which latest several hours. Almost all of the suspected gunmen were reportedly wearing suicide vests, devices usually worn by terrorists on termination missions.
Military officials said two of the terrorists had detonated suicide vests.
By putting down the attackers, the security forces most probably preempted a big hostage-taking too; reports the terrorists had foodstuffs like dates, chickpeas, hand-grenades and petrol bombs suggest they came for the long haul.
What was the motive for the attack?
As usual, the outlawed Tehreek-i-Taliban Pakistan (TTP) claimed responsibility for the Karachi carnage.
"This was revenge for Hakimullah Mehsud's martyrdom" (Mehsud was killed in a U.S. drone strike in November, 2013), and a warning against the impending military operation the government is preparing against the "helpless and innocent tribes in Waziristan," a TTP statement sent to media via email said.
In an earlier message on their Facebook page, the TTP said: "The biggest reason for attacking Karachi airport is because it serves as the biggest air logistics center supplying goods for the Crusaders' war in Afghanistan and Pakistan," referring to the Karachi Port which handles the Afghanistan-bound U.S.-NATO cargo.
Is the first such assault
TTP made a similar claim following a dramatic raid on Peshawar's Bacha Khan International Airport on December 15, 2012.
The group also took responsibility for similar commando raids on the Pakistan Navy airbase PNS Mehran near Karachi in May 2011, followed by a deadly assault on a Pakistan Air Force base at Kamra, 70 kilometers north of the capital, in August 2012.
All three resulted in damage to several air-surveillance and combat aircraft, including a multi-million dollar Saab 2000 surveillance aircraft.
The TTP justified the three attacks as "revenge" for the May 2, 2011 secret U.S. raid that killed Osama Bin Laden in his Abbottabad compound.
At the early stage of investigations, a number of questions and theories can be raised.
Were attackers trying to discredit Pakistan?
The TTP again appears to be at the center of a terrorist pattern that ostensibly aims to hurt he country's economic interests and isolate it internationally.
Following a brazen daylight attack on the visiting Sri Lankan cricket team in March 2009, for instance, all foreign cricket teams refused to visit Pakistan, thus bringing an end to international cricket in the country.
"The only message flowing from these strikes is that foreigners and foreign airlines should not fly into Pakistan," Talat Masood, a retired general told me.
He also recalled the coldblooded execution on June 23, 2013, of 10 foreign tourists in an unprecedented attack in the Himalayas of Nanga Parbat, one of the highest peaks in the world.
The nighttime raid at a height of over 4,000 feet killed three Ukrainians, two Slovakians, one Lithuanian, two Chinese, one Chinese-American, one Nepali and their Pakistani guide -- in what was the worst attack on foreigners in Pakistan in a decade.
What was the role of foreign fighters in the Karachi attack?
Major General Rizwan Akhtar, the head of the paramilitary outfit Rangers, who led the operation, hinted at the possible involvement of Uzbek militants in the deadly attack.
"From their appearances they look like Uzbeks but we will wait for DNA tests to say something with authority," Akhtar responded when asked whether foreign terrorists carried out the assault. And this is not the first time officials named Uzbeks as part of an extremely well-coordinated strike.
The TTP appears to enjoy active support of fighters that belong to the Islamic Movement of Uzbekistan (IMU), a dissident group that escaped persecution in Uzbekistan and settled down in the mountainous region of Waziristan between Pakistan and Afghanistan following the Taliban regime's defeat in December 2011.
Particularly since the killing of its leader Tahir Yuldashev in an August 2009 drone strike, the IMU has increasingly gravitated towards al Qaeda central and acted as its militant arm against the Pakistani security apparatus, which it sees as the major stumbling block in its fight for survival in Pakistan.
Did the attackers have inside information?
TTP and its foreign affiliates draw support from "the enemy within."
"Such a coordinated attack is not possible without inside information," Jalam Hussein, a former Pakistan Air Force commodore told me.
"We really have to think very seriously of purging the security apparatus of such inside supporters," he said.
What was the influence of recent peace talks?
The recent breakdown of TTP talks with government also revived a new string of attacks against security and strategic targets; despite a several week engagement, the talks offered by Prime Minister Nawaz Sharif in an attempt to improve internal security led nowhere.
The government and the security forces found it impossible to accept TTP demands like enforcement of Sharia across the board, withdrawal of the army from the tribal regions and a peace zone for itself. And soon after the stalemate became evident, the army began pounding IMU and Chinese Uyghur hideouts in the Waziristan mountains, where the TTP provides them social cover.
The East Turkestan Islamic Movement (ETIM) represents Uyghur Muslims who want an independent Xinjiang and have been reportedly waging a war on Chinese interests from the Pakistan-Afghan border region.
Was the attack linked to a "proxy war?"
Some officials tie the TTP-led terror campaign to the proxy war that both Pakistan and India have been involved in for quite some time.
Some Pakistanis accuse the TTP of being an Indian proxy, while among the Indian and Afghan establishments there are those who treat Afghanistan's Taliban, particularly the Haqqani Network, as Pakistani proxies.
Often, Indian officials blame attacks on Indian interests on the Pakistani spy agency ISI, including the suicide strike at India's consulate in the western Afghan city of Herat last month.
What does the attack reveal about security in Karachi?
Lastly, the Karachi attack, too, exposed the weaknesses in the early warning capacity of the Pakistani security apparatus; while forces on ground managed to engage and neutralize the attackers within five hours -- restoring air traffic by noon -- questions loom over the intelligence.
Hasan Askari Rizvi, a prominent security commentator based at Lahore, wonders as to how such a big number of attackers remained undetected.
This requires a deep introspection and represents a huge challenge for the government and the entire security agencies.
Counter-terrorism would require extremely close coordination, which could possibly help in early warning as well, he said.
The views expressed in this commentary are solely those of Imtiaz Gul.