At least 100 people have been killed in three days of clashes between local and foreign militants in Pakistan, Interior Minister Aftab Khan Sherpao has said.
Mr Sherpao told the BBC that dozens more had been wounded in heavy fighting near Wana in the South Waziristan tribal area close to the Afghan border.
Officials say that most of those killed since Monday were Uzbek fighters with suspected al-Qaeda links.
Local sources say troops have been sent in. The military denies this.
Hundreds of foreign militants fled to the tribal areas after the US-led invasion of Afghanistan in 2001.
The battle west of Wana is between mostly Uzbek fighters and Pashtun tribesmen led by a militant commander called Mullah Nazir.
Earlier, Mr Sherpao told the BBC that 17 local tribal militants had been killed, along with four civilians.
Heavy fighting with mortars and rockets broke out on Monday, punctuated by a brief truce on Tuesday.
Local sources say they have seen 25 bodies.
Independent confirmation of the reports is extremely difficult as access to the area is restricted and telecommunications poor.
Local sources say the army has now sent in ground troops with light artillery and these are firing at Uzbek positions.
"Residents said troops at the army compound fired at least 15 rounds this morning towards the Kalusha and Azam Warsak areas, the scenes of this week's militant-tribesmen battles," the AFP news agency reported.
Reports suggest the latest fighting erupted after Taleban and local tribesmen demanded the mostly Uzbek militants to leave or disarm. But they refused to do so.
Tensions spilled over after an Arab militant was killed on Sunday.
Foreign militants had largely kept themselves to themselves and were not linked to al-Qaeda's anti-Western agenda, but in recent months they are reported to have become more involved in local disputes, observers say.
The latest fighting follows similar clashes in which 19 people were killed earlier this month.
In recent peace deals with the government, the tribesmen had promised to either get rid of the foreigners or prevent them from fighting.
The tribesmen did not take action and the Afghan government and Nato criticised the agreements for creating militant safe havens.
Pakistan's government says this latest battle shows the tribesmen are now turning against the foreign fighters.
"It is the result of government policy that the local tribesmen are acting against foreign militants," Mr Sherpao told The Associated Press news agency.
But the BBC's Barbara Plett in Islamabad says others believe it looks more like an internal power struggle.
Local militants are fighting on both sides and tribal elders are trying to broker a ceasefire. So is at least one senior Taleban commander sent in from Afghanistan.
The militants in Pakistan's tribal areas support the Taleban insurgency against coalition forces in Afghanistan so it is not in the interests of the Taleban to have them fighting each other, our correspondent says.