A NATO general called on Pakistan Thursday to reopen a supply route for troops in Afghanistan "within a reasonable timeframe", two months after it was shut over a deadly border incident.

"We are not in a desperate situation logistically-speaking for the time being, but it is an issue which has to be addressed, and it has to be addressed within a reasonable timeframe," General Knud Bartels, NATO's most senior military officer, told a news conference.

"We have fallback positions along the northern route, but we need definitely to have access to the southern route ... going through Pakistan," Bartels, who heads NATO's Military Committee, told reporters after two days of talks among alliance brass in Brussels.

NATO troops still receive supplies from northern routes in Russia and Central Asian nations.

Pakistan closed its main trading route to Afghanistan in November, choking a major supply line for the 130,000-strong US-led force, following a deadly air strike by the alliance force that killed 24 Pakistani soldiers on the border.

Islamabad rejects a coalition report that blamed the incident on mistakes by both sides and has not said when it will reopen the route.