And even though 28,000 troops are now fighting the Taliban in South Waziristan, the bulk of the army still faces east.

Against this backdrop, imagine how many sleepless nights the prospect of a third front must be causing. The recent attack by Jundallah in Iran's Sistan-Baluchestan province has raised the spectre of hot pursuit into Pakistani Balochistan.

Although this is not an imminent prospect, there are Iranians who are itching to cross the border to crush this terrorist group that has been a thorn in their country's side since it was established in 2005 by its leader, Abdolmalek Rigi.

Jundallah (not to be confused with Jandola, a Pakistani terrorist group) came into being to supposedly protect the rights of the Sunni Baloch in Iran. However, its close links with drug smugglers and the Taliban in Afghanistan make it anathema to Tehran, and its deadly campaign against the Iranian state has caused scores of casualties.

But even more controversial are the allegations that it has enjoyed CIA support, at least in the recent past. In April 2007, ABC, the American network, carried a report by Brian Ross and Christopher Isham alleging that Jundallah was receiving covert American support.

The story also alleged that the group was based in Pakistan. Other reports asserted that the then US Vice President Dick Cheney discussed Jundallah with Musharraf on a visit to Islamabad.

These allegations tied in neatly with a report by Seymour Hersh, the prize-winning reporter. Published by the New Yorker in July 2008, Hersh wrote that congressional leaders had secretly approved a request for $400m from George Bush to finance covert operations against Iran in a bid to slow down or halt its nuclear programme.

These efforts included clandestine operations, anti-Iran propaganda, and support for terrorist groups like the Mujahideen-i-Khalq. It is unclear whether the Obama administration has terminated this campaign.

Obviously, no Pakistani official in his right mind would wish to be involved in a suicidal policy to help Jundallah in its attacks against Iranian targets. Despite the ups and downs in our relationship with Iran, we have tried to minimise differences, even at the time of tension when Pakistan supported the Taliban, even while they persecuted Afghanistan's Shia minority when they were in power.

Nevertheless, all too often in Pakistan, the right hand doesn't know what the left is doing. Some arrested Jundallah militants in Iran have confessed they were trained at a secret camp in Pakistani Balochistan. Whether there was an element of official connivance is hard to say.

Many years ago, while driving from Europe, I crossed the bleak vastness of Sistan. The desert stretched for miles, and there were few signs of human habitation in that barren moonscape. Entering Pakistan, the landscape was much the same.

Although I have not been to that part of Balochistan for some years now, I doubt if much has changed. The terrain is inhospitable and forbidding, and sealing off this border between Iran and Pakistan is clearly not feasible.

Nevertheless, the presence of Jundallah in this desert is causing grave concerns in Tehran and Islamabad. Should the evidence Iran says it has linking Jundallah to Pakistan prove to have weight, our deadly dalliance with extremist terror groups will further erode our security instead of strengthening it.

An issue no Pakistani government has yet faced relates to our open, often unmarked and poorly defended borders. With the exception of our border with India — probably the most militarised in the world — our Kashmir, Afghan and Iranian frontiers are either porous or disputed, or both.

In Gwadar a few years ago, I was surprised to see a large number of pick-ups full of goods driving along the long, flat beach. I was told they were the normal traffic between the city and Iran, and brought in everything from chickens to petrol. Nobody has tried to halt this flow of smuggled goods as it's cheaper to get them from Iran than it is from Karachi.

This same pattern can be seen on the border of Afghanistan and Pakistan. Called the Durand Line, it has not been accepted by any Afghan government since the British imposed it on Kabul in 1892. I don't know about current tastes, but when I was there a long time ago, Pakistani K-2 cigarettes were the most popular brand in much of Afghanistan. Pakistani toiletries were available everywhere.

Needless to say, these items were smuggled across, just as imported electrical goods destined for Afghanistan are still being sold across Pakistan.

All this easy movement across borders might have been a good thing had it been limited to bars of soap and other items. But over the years, these smuggling routes have witnessed large numbers of poor people trying to find the promised land in Europe; drug smugglers moving large quantities of heroin and opium; and gunrunners transporting sophisticated arms across Pakistan.

Complicit in this illegal cross-border traffic on both sides are security forces as well as immigration and customs officials. Exploiting these laxly controlled borders, terrorist groups have operated with impunity for years, sending militants to launch attacks without let or hindrance.

Thus far, these militant operations have caused Pakistan to be placed on the defensive by the Afghan and Indian governments. Now Tehran has joined this list of angry neighbours. China has privately expressed its concerns about the activities of Pakistani extremist groups in its Muslim areas.

Even more than porous borders, it is the increasingly religious environment in Pakistan that is proving conducive to the most rabid and violent activism. Those of us who are still in denial about this phenomenon need to ask themselves why it is that Pakistan has become a magnet for extremists from all corners of the globe.

Of course the other factor that is driving Islamic militancy in Pakistan is the steady erosion of the writ of the state. Permitting millions of Pakistanis in the tribal areas to bear arms because it was their custom has resulted in a proliferation of weapons across the country. And all too often, militants get off scot-free after committing the most bloody deeds.

Now that the army has finally gone into action to crush the Taliban in South Waziristan, we need to ensure that the momentum of the fight is maintained, and these killers are not granted safe haven anywhere on Pakistani soil.

irfan.husain@gmail.com