ISLAMABAD // Pakistan's leaders have authorised the government to complete an agreement to reopen overland Nato supply routes to Afghanistan that Pakistan closed six months ago after 24 of its soldiers were killed by accident in a Nato air strike.

Islamabad had risked being excluded from a Nato summit in Chicago this weekend if it failed to reopen the routes.

Shortly before Pakistan's Defence Committee of the Cabinet announced its decision on Tuesday night, Nato invited Asif Ali Zardari, the Pakistani president, to attend the summit. Qamar Zaman Kaira, the information minister, told a news conference yesterday that Mr Zardari would attend.

Speaking to a cabinet meeting yesterday, the prime minister Yusuf Raza Gilani said Pakistan's relations with the United States and Nato were passing through a "delicate phase" and the government had to take "critical decisions".

Pakistan is an important US ally in the war against terrorism but relations deteriorated after the US special forces raid that killed Osama bin Laden in a Pakistani town in May last year and the Pakistani soldiers' deaths in the air raid last November.

Pakistan retaliated by closing the supply routes through which Nato transports 40 per cent of its non-lethal supplies to Afghanistan.

Pakistan's parliament last month recommended that the government should seek an unconditional apology from the US for the air-strike deaths. The US has said it regrets the incident but has refused to apologise.

Mr Gilani's office said in a statement that military authorities had been asked to negotiate "fresh border ground rules" to avoid incidents such as the one in November.

The reopening of supply lines is a sensitive issue in Pakistan where anti-American sentiment runs high. But analysts said Pakistan could not afford to be excluded from international efforts to stabilise Afghanistan. Moreover, Pakistan depends on billions of dollars in US aid to keep its economy afloat.

"They made the point by closing routes for six months that there are certain red lines," said the retired general turned security analyst, Talat Masood. "But they have to show the flexibility in the larger interest of the country because they thought they would be internationally isolated if they did not open it … it's a wise decision."

However, the opposition called the move a "sell-out".

"It's a shame," Nisar Ali Khan, an aide to the former prime minister Nawaz Sharif and the opposition leader in the National Assembly, told Geo television. "They have done it for the sake of just an invitation" to the Chicago summit.

Despite the imminent opening of the supply routes, the troubles between Washington and Islamabad are far from over.

Pakistan's parliament has called for an end to US drone strikes against militants operating in Pakistan.

Pakistan also complains about slow payments from the Coalition Support Fund, which reimburses Pakistan for the use of its infrastructure in the war on terrorism.

The US, in turn, has been demanding that Pakistan acts decisively against militants.

US officials also suspect that Pakistan's main spy agency, the Inter Services Intelligence, maintains ties with militant groups in a bid to use them as a bargaining chip in the political settlement of the Afghan issue.

foreign.desk@thenational.ae