The fourth suicide attack in less than a week targeted a joint army and paramilitary checkpoint near Mir Ali -- one of the biggest towns in the lawless tribal zone of North Waziristan, which borders Afghanistan.

Suspected Islamists also blew up two security checkpoints in Miranshah, another town in the same region but there were no reports of casualties. No one claimed responsibility.

However, militants earlier this week distributed pamphlets in the region, which warned the government and the military of imminent attacks shortly after the Taliban Shura Council tore up a peace accord negotiated by the government and tribal elders last September.

The militants said they had torn up the deal because the government had flouted it by setting up new checkpoints in the area, and because it had not paid compensation for the death of tribesmen in army operations.

Criticism

Both Afghanistan and the United States had criticised the deal, under which the militants vowed to stop cross-border attacks and to help the army hunt down foreign insurgents hiding in Pakistan's lawless North Waziristan agency on the Afghan border.

Since the militants' announcement on Sunday to cancel the deal, Islamabad has increased security and has declared eight "sensitive areas", including North and South Waziristan and Malakand.

There have been ongoing negotiations since the weekend between government-backed tribal elders and militant leaders. The government hopes the tribal elders will be able to convince the militants to stick with the deal and has reiterated it will compensate people injured by earlier military operations.

Some hope

Akram Khan Durrani, the Chief Minister of North West Frontier Province or NWFP, told the media there were positive signs and said the tribal elders had given the government a "commitment".

"They said that they are with the government and they are very responsible people," he said. "The best solution is to use this jirga now .They have given us 15 days to come up with asolution and recommendations."

"Dangerous consequences"

Despite some elements of hope, two government representatives returned empty-handed to Peshawar, the capital of NWFP and the governor, Ali Mohammad Jan Oradkzai, expressed his fears.

"Unfortunately, if the September peace deal collapses, the consequences will be dangerous and the fallout will affect settled areas as well," he said. "We are doing our best to keep the deal."

Outcome of failed policies

Meanwhile, the opposition leader in the provincial assembly, Maulana Fazl Ur Rehamn, said all this was the outcome of the government's failed policies.

"We told the federal government so many times that if they used force at the Red Mosque, things would definitely get out of control," he said. "We all know that the real problem lies with Afghanistan and that it affects bordering tribal areas and North-West Frontier Province."

The September accord, which some experts say never really got off its feet, was supposed to open the way for an extensive development programme for which the US had pledged $750 million over the next five years.

However, following the weekend attacks, the State Department has said that it may introduce safeguards to ensure that the aid it plans to pour into the tribal areas does not fall into the wrong hands.