KABUL: Pentagon chief Chuck Hagel heads to Pakistan on Monday for talks as Washington seeks to defuse tensions over controversial US drone strikes and Islamabad's role in Afghanistan.

In the first visit by a US defence secretary in nearly four years, Hagel will fly from Kabul to Islamabad to meet Prime Minister Nawaz Sharif and other top officials, including the country's new army chief.

Ties between Washington and Islamabad have been seriously strained over US drone strikes in Pakistan's tribal belt as well as Afghan Taliban sanctuaries inside Pakistan's borders.

“Secretary Hagel met with Prime Minister Sharif on his visit to Washington earlier this year and looks forward to continuing candid and productive conversations,” Pentagon spokesman Carl Woog told reporters on Sunday.

The visit was announced as Hagel's deputies said Nato shipments out of Afghanistan through Pakistan would resume after the end of anti-drone protests.

In recent weeks, activists opposed to the drone raids forcibly searched trucks in the Khyber Pakhtunkhwa province in a campaign to disrupt Nato supply routes to and from Afghanistan.

The club-wielding protesters prompted US officials to temporarily halt the shipments to protect the safety of truck drivers ferrying Nato equipment.

But a US defence official told reporters in Kabul that the suspension of shipments via Pakistan had been lifted because the protests had stopped, removing the threat to Nato trucks that move through the Torkham gate pass.

The crossing is the main overland route used by the Americans and Nato to withdraw tonnes of military hardware from Afghanistan as part of a massive troop pullout set to wrap up by the end of 2014.

President Barack Obama has defended the drone strikes as an effective, lawful tool used with restraint to target suspected Al Qaeda militants. But human rights groups and Pakistani politicians say the missile attacks have killed innocent civilians and must stop.

As part of his brief visit to Islamabad, Hagel was expected to meet the country's newly appointed army chief, General Raheel Sharif.

The position holds special significance in Pakistan and US officials are anxious to forge a constructive dialogue with a figure expected to be at the centre of decision making on sensitive security questions.

The veteran infantry commander last month succeeded General Ashfaq Kayani, who is retiring after six years at the helm.

Hagel's spokesman said the defence secretary looked forward to discussing with his counterparts “the United States and Pakistan's common interest in a stable Afghanistan.”Pakistan is seen as crucial to peace in neighbouring Afghanistan as it was a key backer of the hardline 1996-2001 Taliban regime in Kabul and is believed to shelter some of the movement's leaders.

Hagel was headed to Pakistan after two days in Afghanistan, where he urged the country's president, Hamid Karzai, to sign a long-delayed security agreement that will allow Nato-led forces to stay in the country after 2014.

Hagel began his trip last week in Bahrain, where he sought to reassure Gulf allies that the United States would retain a robust military presence in the region despite an interim nuclear deal with Iran.

After morning meetings in Pakistan, Hagel was due to travel to Saudi Arabia and Qatar, where he was expected to renew his message of solidarity with the Gulf Arab states.

The Saudis in particular are wary of the diplomatic opening with Tehran as they view Shia-led Iran as a regional rival.