An amnesty deal for foreign militants in Pakistan's Afghan border region has suffered a setback, with them failing to begin registering as agreed.
The tribesmen could face legal action if the deal fails
Under the deal, the fighters would be able to stay if they halted activities against Pakistan and Afghanistan.
Pakistan has now given local tribesmen who brokered the deal more time but said they might face legal action if they failed to deliver.
Hundreds of foreign militants are thought to be hiding in the region.
They led stiff resistance to a huge army operation in the South Waziristan region in March to root out militants accused of al-Qaeda links.
'Patience running out'
Local tribesmen are now believed to be pursuing more consultations with the foreign fighters - mainly Arabs, Uzbeks, Chechens and Afghans.
But Asmatullah Gandapur, an administrator in South Waziristan, told 100 local tribal elders in the region's main town, Wana, on Friday that the government's patience was running out.
"We are working with full restraint but if tribesmen do not fulfil their collective and territorial responsibilities, the law will take action against them," Mr Gandapur told the Associated Press news agency.
In Pakistan's semi-autonomous tribal areas, whole clans can be held responsible for an individual's actions.
One tribal elder, Malik Mohammed Iqbal, said registration might not now begin until Sunday.
"Many people have to come from far-off places. They will take time to reach here," he told AP.
Wednesday's announcement that the fighters had agreed to the amnesty deal came after two deadlines set by the Pakistani authorities for foreigners to register or face renewed force had passed.
More than 100 militants and troops were killed in the fighting in March.