“We are in a very difficult time right now in our military-to-military relations,” Joint Chiefs of Staff Chairman Admiral Mike Mullen told a press briefing billed as his last before retirement. —AP photo

WASHINGTON: The top US military chief warned Monday that US-Pakistan military-to-military ties were at a “very difficult” crossroads, allowing that a path to progress on that front was not yet clear.

President Barack Obama’s administration recently suspended about a third of its $2.7 billion annual defense aid to Pakistan in the wake of the raid that killed Osama bin Laden near the country's main military academy.

But it assured Islamabad it is committed to a $7.5 billion civilian assistance package approved in 2009.

“We are in a very difficult time right now in our military-to-military relations,” Joint Chiefs of Staff Chairman Admiral Mike Mullen told a press briefing billed as his last before retirement.

Despite the strain, Mullen said “I don't think that we are close to severing” those ties. And the retiring admiral said he hoped the two nations would soon find a way to “recalibrate” those ties.

Still, Mullen acknowledged: “we need to work through the details of how this (recalibration) is going to happen.”

Top US officer Mullen has suggested that Pakistan's army or Inter-Services Intelligence agency likely killed journalist Saleem Shahzad, who had reported about militants infiltrating the military.

On a visit to Washington, Pakistan's former military ruler Pervez Musharraf staunchly defended the army and ISI. He denied any Pakistani support for bin Laden, who apparently moved to the garrison town of Abbottabad while Musharraf was in power.

US officials have long questioned Pakistani intelligence's ties with extremists, including Afghanistan's Al-Qaeda-linked Haqqani network and the anti-Indian movement Lashkar-e-Taiba that allegedly plotted the grisly 2008 assault on Mumbai.

Admiral James Winnefeld, nominated to be the number two US military officer, described Pakistan as a “very, very difficult partner.”

“We don't always share the same worldview or the same opinions or the same national interest,” Winnefeld told his Senate confirmation hearing last week.

Obama has nominated General Martin Dempsey as chairman of the Joint Chiefs of Staff; Dempsey is due to succeed Mullen, who is retiring at his term's end September 30.