And American taxpayers pay roughly a quarter of the ISI’s annual operating budget.

(Reuters) — U.S. officials say there is mounting evidence that Pakistan’s chief intelligence agency has been encouraging a Pakistan-based militant network to attack U.S. targets.

The allegations, if fully confirmed, heighten a painful dilemma for President Barack Obama’s administration. Washington is under growing political pressure to take action against the Haqqani network after a spate of deadly attacks U.S. officials have attributed to it. These include last week’s strike against the American Embassy in Kabul, Afghanistan.

Some U.S. intelligence reporting alleges that Pakistan’s Inter Services Intelligence directorate (ISI) specifically directed, or urged, the Haqqani network to carry out the September 13 attack on the embassy and a NATO headquarters in Kabul, according two U.S. officials and a source familiar with recent U.S.-Pakistan official contacts. However, officials cautioned that this information is uncorroborated.

Another U.S. official familiar with internal government assessments said that at the very least, the available intelligence strongly suggests the ISI has been egging on elements of the Haqqani network to launch attacks at American targets in the region.