Pakistan's army chief has denied accusations that the military is working to oust the country's civilian government amid tension over a secret memo sent to Washington earlier this year about an alleged coup.

The memo scandal has heightened long-standing tensions between the army and the government at a time when the country is struggling to deal with a violent Taliban insurgency, a faltering economy and deteriorating relations with its most important ally, the United States.

The Pakistani Prime Minister, Yousuf Raza Gilani, claimed that there was a conspiracy under way to topple the government. He did not point to the military, but said the army must be answerable to parliament and cannot operate as a "state within a state".

The Army chief, General Pervez Ashfaq Kayani, denied the claims and pledged the force would continue to support democracy in Pakistan.

"The army is fully cognisant of its constitutional obligations and responsibilities," General Kayani said.

The army has ruled the country for much of its 64-year history after carrying out a series of coups. Analysts have doubted that a coup is likely at this time, but have speculated that the army may try to pressurise the country's embattled president to resign over his alleged role in the memo scandal.

Pakistan's former ambassador to the US, Husain Haqqani, has been accused of being behind the memo, which asked Washington to help avert a supposed coup in the aftermath of the unilateral American raid that killed Osama bin Laden in a Pakistani garrison town in May. Mr Haqqani allegedly acted with President Asif Ali Zardari's support. Mr Haqqani and the President have denied the allegations, but the envoy resigned in the wake of the scandal.

AP