Pakistan has stopped the United States from using an air base in the southwest of the country which it is alleged to have used to launch controversial drone strikes, according to the country's defence minister.

Ahmed Mukhtar told journalists on Wednesday that US officials had been told to leave the Shamsi base in the southwestern province of Baluchistan, Pakistani state media reported.

The UK's Financial Times newspaper quoted Mukhtar as saying that Pakistan had ended US drone flights out of base, long reported to have been used for a campaign of air strikes targeting al-Qaeda and the Taliban fighters in the northwest region along the Afghan border.

"No US flights are taking place from Shamsi any longer. If there have to be flights from the base, it will only be Pakistani flights," Mukhtar said.

But a US military official told Al Jazeera that there were no US forces at the Shamsi base, and that claims they had been told to leave were therefore untrue.

A Pakistani official told the Financial Times that no drone flights had taken off from the base since 2009.

Islamabad has long publicly opposed the missile attacks as a violation of its sovereignty, but has in private given support including intelligence to help target alleged al-Qaeda and Taliban members.

A Google Earth image dated 2004 appears to show three drone-like aircraft parked at the airbase.

Kamal Hyder, Al Jazeera's correspondent in Islamabad, said that the Shamsi air base had been given to the US under Parvez Musharraf, Pakistan's president from 1999 to 2007.

"When the US drone attacks intensified in the tribal areas, [they] caused growing anger in Pakistan and the government was consequently put on the back foot," our correspondent said.

Ties between the countries, strained since the killing of two Pakistanis by a CIA agent in January, suffered a further setback when US special forces killed al-Qaeda leader Osama bin Laden in a secret raid that Pakistani officials said further breached its sovereignty.

Hyder said the operation against Bin Laden had put Pakistan in an embarrassing position, prompting them to "tone down the American military presence on the ground".

Pakistan's army has drastically cut down the number of US troops allowed in the country and set clear limits on intelligence sharing with the United States, reflecting its anger over what it sees as continuing US interference in its affairs.

US drone strikes have been stepped up since American President Barack Obama took office.

Attacks have further intensified since bin Laden's killing which reinforced suspicion in the United States that elements of Pakistan's security establishment may have helped hide him.