ISLAMABAD: Pakistan's border with Afghanistan was closed Thursday and security forces were on alert as Afghans voted in national elections under threat of Taliban attacks, officials and residents said.

An insurgency by the extremists plagues both Muslim states, with militants slipping over the porous border and also staging attacks on convoys supplying NATO troops as they travel from Pakistan to war-torn Afghanistan.

"The Pak-Afghan border has been completely sealed from Tuesday and will be closed till Friday... security is on high alert on both sides of the border," said Rehan Gul Khattak, assistant administrative chief for Khyber district.

"The containers carrying goods for NATO forces have also been stopped and there are long queues of supply vehicles on the border."

Khattak was referring to the official border posts, but much of the traffic along the 2,500-kilometre (1,500-mile) frontier is through informal crossings or deep in the remote mountains where there is no government presence.

The Khyber official said that Afghans who had special passes from their embassy allowing them to vote would be able to cross, but added that only about 200 people had passed through the busiest border post at Torkham.

Officials and locals in Pakistan's Balochistan province, which borders Afghanistan, said the main Chaman border crossing had also been closed.

"We had a meeting with the Afghan authorities a few days ago in which it was decided that the border be closed for the peaceful holding of elections," said Murtaza Beg, spokesman for the Frontier Corps, which guards the border.

"Following the Afghan government's desire we have closed all entry and exit points," he added.

About 1.7 million Afghan refugees remain in Pakistan after fleeing civil war and Taliban rule in their homeland, according to United Nations figures, while hundreds of thousands more are believed to be here illegally.

There are about 860,000 official refugees of voting age living in Pakistan, the UN says. But unlike in Afghanistan's first presidential elections in 2004, no provisions have been made for them to cast absentee ballots.

"I am sad and feeling helpless as I can't cast my vote in this very important election," said Ghulam Raza Sakhi, 37, an owner of an Afghan clothing store in the Pakistani capital Islamabad.

"We are in big numbers here and can play a positive role for a change," said the 37-year-old, who has lived in Pakistan for 20 years.

Twenty-one-year-old Nadeem Ghafari could be voting for the first time, but instead says he is "disappointed" to be staying in Pakistan.

"There should be a change, peace, prosperity and development, no matter who wins," he said. LINK