(CNN) -- A Pakistani court on Tuesday indicted former President Pervez Musharraf in the killing of opposition leader Benazir Bhutto, the first time charges have been filed against an ex-military chief in the South Asian nation.

Bhutto, Pakistan's first female prime minister, was assassinated in a gun-suicide attack in December 2007, shortly after she came back to Pakistan from self-imposed exile to take part in the 2008 general elections. Musharraf was president at the time.

Musharraf's government blamed former Pakistani Taliban leader Baitullah Mehsud for the assassination, saying he had paid a network of Islamist militants to carry out the killing.

But Musharraf and his security forces were previously accused of failing to do enough to protect Bhutto, a political rival.

The former military ruler has denied having anything to do with Bhutto's killing.

"The politically motivated indictment filed against Former President Musharraf implicating him in the unfortunate assassination of former Prime Minister Benazir Bhutto is not only false, fabricated and fictitious, but is also an undignified attempt to smear the honor and integrity of the former president on the world stage," Musharraf spokesman Raza Bokhari said in a statement Tuesday.

After the general elections in 2008 where his party was trounced, Musharraf stepped down as the governing coalition began taking steps to impeach him.

He then went into self-imposed exile.

Earlier this year, he returned to Pakistan in an attempt to revive his political career. It didn't work.

Instead, he's become entangled in a thicket of court cases related to his time as the country's top leader. He has been under house arrest since April.

Other cases relate to the detention of judges in 2007 and the killing of a tribal leader in the volatile province of Balochistan.

The recently elected government of Prime Minister Nawaz Sharif, a longtime political foe of Musharraf, has also suggested that the former military ruler should stand trial for treason.

Sharif has accused Musharraf of illegally abrogating the constitution in November 2007.

That month, Musharraf declared a state of emergency, suspended Pakistan's constitution, replaced the chief judge and blacked out independent TV outlets.

Musharraf said he did so to stabilize the country and to fight rising Islamic extremism.

Such a prosecution of a former top general would be likely to strain the already delicate relations between Sharif and Pakistan's powerful military.

CNN's Khushbu Shah contributed to this report.