"Analysts said that visit was meant to signal to the United States that Pakistan saw China as an alternative source of security and economic aid."

"Pakistani soldiers exchanged fire with two NATO helicopters
that crossed into Pakistan’s airspace from Afghanistan early Tuesday,
the Pakistani Army said,
as United States senators increased calls in Washington
to suspend or put conditions on billions of dollars in American aid to Pakistan.

The firefight, in which Pakistan said two of its soldiers were wounded,
marked the latest episode in a rapidly deteriorating relationship
between the United States and Pakistan in the wake of the Navy SEAL raid
that killed Osama bin Laden on May 2.

That Bin Laden was discovered at a compound not far from the capital
has heightened American distrust of Pakistan,
while the raid inflamed Pakistani sensitivities over sovereignty.

Since then, the Obama administration and its allies in Congress
have scrambled to keep tensions from spinning out of control
and provoking Pakistan to shut down transit routes into Afghanistan
that supply United States troops there.

Those tensions were laid bare on Capitol Hill on Tuesday
as Democrats and Republicans voiced anger and bewilderment
at providing $3 billion a year in aid to Pakistan,
only to have that nation’s leaders criticize the United States
for violating Pakistan’s sovereignty during the raid on Bin Laden’s house in Abbottabad,
a small city about 70 miles from the capital that is home to a major military academy.

...An American military official said the Pakistanis were injured by a rock slide, not gunfire.

...Last September, Pakistan shut down the land route through Pakistan
that NATO uses to supply its forces in Afghanistan for more than a week
after two Pakistani paramilitary soldiers were killed in a similar border clash.

...The clash on the border came as Pakistan’s prime minister, Yousaf Raza Gilani,
traveled to Beijing.

Analysts said that visit was meant to signal to the United States
that Pakistan saw China as an alternative source of security and economic aid."

NYT