At least eight Pakistani soldiers were killed in clashes after militants attacked a checkpost in the country's lawless tribal northwest on Wednesday, officials said.

Dozens of militants armed with rockets and grenades stormed the checkpost in Surang Baba Ziarat village, around 30 kilometres (20 miles) north of Wana, the main town of South Waziristan tribal district, a senior security official in Peshawar told AFP.

The attack came during a military operation against militant hideouts which netted a huge cache of arms and ammunition, the official said.Eight soldiers were killed and six injured in the checkpost attack, the official said, while 18 militants died during three hours of fighting. A second security official confirmed the military death toll.

The area is cut off to journalists and aid workers and it was not possible to confirm the death toll independently.Pakistani Taliban spokesman Ehsanullah Ehsan claimed in a telephone call that the militants had killed more than 12 soldiers and only one militant had died, though the group often exaggerates military casualties.

South Waziristan is one of seven districts in Pakistan's semi-autonomous tribal belt, where Taliban and Al Qaeda-linked militants have carved out strongholds used to plot attacks on Pakistan.

Pakistan has lost more than 3,000 soldiers in the fight against homegrown insurgents but has resisted US pressure to do more to eliminate havens used by those fighting the Americans in Afghanistan.