Tens of thousands of people have fled Pakistan's lawless tribal region ahead of an expected army offensive, officials said Wednesday, as fighter jets continued to pound Taleban positions and more soldiers and tanks moved in for an expected offensive against the militant hub. Authorities have registered 90,000 people displaced from south Waziristan on the Afghan border since August, with a fresh exodus after a weekend hostage siege at army headquarters near Islamabad. The government says most attacks in the country - including four major ones since Oct. 5 that killed more than 100 people - are plotted in South Waziristan on the Afghan border. “It was intense bombing. Three hideouts were hit,” Mohammad Khalid Khan, a senior government official in the region's main town of Wana, said. Khan did not have information about casualties but intelligence officials in the region said at least 10 militants were killed. Residents in the area said the military was sending more soldiers into mountains overlooking Makeen, a main stronghold of militants. “We've seen many tanks coming here since yesterday. Some went to their camp while others were deployed in the mountains,” said Sayed Wali, a resident of Shankai village. – AgenciesThe government in June ordered the army to launch an offensive in south Waziristan. Since then the military has been conducting air and artillery strikes to soften up the militants' defences. ‘Ready for assault' The government says the assault is imminent but it will be up to the army when they send in ground troops. A ground offensive in south Waziristan could be the army's toughest test since the militants turned on the state. The army has not said when it would begin but a senior military officer in the region told Reuters that they were set. “We're ready for the assault. Preparations have been done. It's just a matter of the go-ahead order,” said the officer who declined to be identified. “It'll be done from multiple directions to squeeze them,” he said. About 28,000 troops have been put in place to take on an estimated 10,000 Taleban, army officials have said. But some analysts worry that might not be enough, especially if the army has to block militants from other factions based in North Waziristan coming to the help of their comrades.