Bara: Heavily armed paramilitary troops blocked roads into a tribal town in northwestern Pakistan and patrolled its deserted bazaar yesterday as an operation against militants rolled into its fifth day with more arrests but no sign of fighting.

Troops arrested ten suspected supporters of a local militant chief, Mangal Bagh, and confiscated submachine guns, rifles and ammunition from their pickup truck, about five kilometres from Bara, the focus of the operation in Khyber tribal region.

The blindfolded captives were displayed to reporters who visited a Frontier Corps base, which had about a dozen tanks, several armoured personal carriers and artillery guns inside.

A senior officer, who sought anonymity as he was not authorised to speak to the media, said the men were detained as they attempted to transport the weapons in the remote Tirah Valley.

Key supply line

Rival militant groups Ansar-ul-Islam and Bagh's Lashkar-e-Islam - which have gained sway in Khyber in recent months - have fought with each other in the valley this week, even as Pakistan launched the military operation in the more accessible area around Bara.

The aim of the operation is to protect nearby Peshawar, the capital of North West Frontier Province.

The main road through Khyber is also a key supply line for US and Nato forces in Afghanistan.

The offensive comes amid growing concern that Pakistan, a key US ally in its war on terror, is losing control of its volatile northwest, making it easier for Taliban and Al Qaida militants to launch cross-border attacks.

In Islamabad, visiting US Assistant Secretary of State Richard Boucher said the operation outside Peshawar was "very welcome ... but it's a reminder of how much of a problem there is up in that part of the country," he said at a news conference, adding that security in the area appeared to have deteriorated in the past two years.

In an interview with Bagh aired yesterday he denied he had plans to capture Peshawar or had ever fought against the government.

Since the military operation began, authorities say forces have destroyed several militant centres, and recovered some men but only one militant has been reported killed in fighting.