HEART: One of Afghanistan's safest areas, the region around Herat, risks falling prey to increased violence as troops flood in to try to quell the Taliban-led insurgency, NATO officers and diplomats say.

The western region, relatively rich by Afghan standards, has become NATO's ‘great unknown’ in security terms, according to alliance documents, as approaching elections bring new uncertainty about the Taliban's intentions.

Squeezed by the arrival of some 17,000 troops in the south, the insurgents, backed by Al-Qaeda and criminal gangs, have begun moving north toward Herat along routes sometimes used by opium smugglers to ship their loads to Iran.

‘The Taliban, when they are under pressure, they escape. They can escape in two main directions, south toward Pakistan and north towards us,’ said Italian General Rosario Castellano, head of the NATO-led contingent here.

Castellano commands some 3,900 international troops, but they watch over an area around half the size of Italy, leaving swathes of land with no military presence whatsoever.

Part of it, the province of Farah with a largely Pashtun population— like the Taliban—   borders Helmand, where opium poppy cultivation has flourished and provides funds to groups determined to undermine the weak central government.

‘We think that a lot of them are going to Farah right now,’ said US Colonel Gregg Julian, with US forces in Afghanistan.

‘But they're going to fight hard for Kandahar and Helmand, because the majority of their poppy crop and their drug funding for the insurgency comes from that area. They're not going to give up easily.’ Officials and military personnel were uneasy about the lack of insurgent violence when Afghans registered a few months back for the presidential and provincial elections on August 20.

Some suspect this may have been because the Taliban want to try to establish some political legitimacy. Others claim the fighters wanted to secure identity cards handed out during registration which would allow them to move around more easily.

But it is unclear how the insurgents will react on polling day, by which time thousands more troops will have deployed to ensure the smooth running of an election considered a stern test of NATO's efforts to foster democracy here.

‘We are concerned of course,’ one European diplomat said.

For those keen on a show of force, ‘it is their big moment. There will be a lot of international attention on the country, so if you want to make a mess of it, it's a good time.’ Another great unknown for NATO is the attitude of Iran, which like many of Afghanistan's neighbours is being courted by the West to help bring stability.

The Islamic republic's economic and cultural influence around Herat is undeniable.

But diplomats and officers claim that Iran tolerates and even aids the Taliban, allowing fighters to rest on its territory or permitting small arms to flow across the roughly 450 kilometres (280 miles) of border in this region.

‘They allow training in Iran,’ an officer with the NATO-led International Security Assistance Force (ISAF) said.

‘There is evidence of some small arms going to the insurgency. But it hasn't breached a threshold of heavy weapons.’ Iran— where a significant number of people suffer from drug addiction exacerbated by Afghan poppies— has meanwhile used the expulsion of illegal immigrants from over the border as a means to pressure Kabul.

‘Cyclically, Iran tries to push over more people for political reasons,’ one European military officer said.

Military estimates suggest some 3,000 Afghans illegally enter Iran each day. But the number that Tehran threw out over the first five months of this year increased by 72 percent over the same period in 2008.

Iran's influence, the unpredictability of the Taliban as troops move into their southern heartland and the pressure-cooker atmosphere of elections have combined to dampen the optimism of Western officials in this region.

‘Most observers expect a worsening of the security situation in the province,’ the European diplomat said. ‘We remain prudent.’