ISLAMABAD, (Reuters) – Pakistan’s army has ended its offensive against the Taliban in South Waziristan and is shifting focus to another tribal area to where many militants have fled, the prime minister said on Saturday.

The operation in South Waziristan, which borders Afghanistan, was the army’s biggest in years involving 30,000 troops. Military officials were not available to say if it had achieved its goals.

“The operation has finished in South Waziristan. Now there is talk of Orakzai,” Prime Minister Yusuf Raza Gilani told reporters in the eastern city of Lahore.

Pakistan’s military say 589 militants and 79 soldiers have been killed in the South Waziristan campaign since it was launched in mid-October. Militants have hit back with bombings that have killed hundreds of people.

Security officials say many of the militants are believed to have fled South Wazirstan to Orakzai, North Waziristan and the Kurram tribal areas.

Orakzai is believed to be the base of Hakimullah Mehsoud, leader of Pakistani Taliban insurgents, and a global hub for al Qaeda and other militant groups.

Intelligence officials say paramilitary forces have been carrying out crackdowns on the militants in Orakzai for several weeks. War planes also often attack militant targets.

Government forces now control much of the territory held by forces loyal to Mehsud but they still face pockets of resistance, officials said.

U.S. attempts to push Pakistan to root out Taliban and al Qaeda fighters in the lawless tribal regions, as well as American drone aircraft attacks on suspected militants, have created intense anti-American sentiments in Pakistan.

U.S. President Barack Obama has said victory in Afghanistan will only be possible with strong Pakistani cooperation and stronger efforts to wipe out militant sanctuaries.

Pakistani officials fear his plans to send 30,000 more U.S. troops to Afghanistan will push militants over the border and create new pressures for the Islamabad government.

U.S. ally Pakistani President Asif Ali Zardari is fighting for his political survival so he may not be in a position to persuade the powerful military to focus on border areas while it tries to stamp out a Taliban insurgency.