Afghanistan is heading for a bumper poppy crop

Customs officials in western Pakistan have seized more than a tonne of heroin, in what they say is the country's biggest-ever haul of the drug.

The raid came after a fierce gunfight following a tip-off in Balochistan Province near the Afghan border.

A number of suspected smugglers escaped.

Customs officials said the 1,350 kilograms of heroin were worth more than $500m on the international market.

"The drug was destined for Iraqi Kurdistan via Iran from where it was to be smuggled to some European countries," Assistant Collector of Customs Abdul Waheed Marwat told reporters in the provincial capital, Quetta.

There was an exchange of gunfire between customs and heroin smugglers during the raid but no one was hurt Abdul Waheed Marwat Pakistan Customs

"This is the biggest-ever catch of heroin in Pakistan."

The drugs were packed in plastic bags, each containing a kilogram of heroin.

Raids

Officials said the heroin was of the highest quality, and suspect it was smuggled from neighbouring Afghanistan.

The UN International Narcotics Control Board says that opium cultivation in Afghanistan - used in heroin and other drugs - is now as widespread as in the 1990s.

In March, Pakistani officials said Afghanistan was heading for a record opium poppy crop this summer.

On 6 April the Pakistani authorities seized 1,220 kilograms of opium in Baluchistan on the Iranian border.

Pakistan seized 1.13 tonnes of morphine on 23 December in the same region.