The steady drum beat of high-profile kills in Pakistan — including Usama bin Laden's son and Baitullah Mehsud, commander of the country's Taliban — suggests that U.S. intelligence on the ground has crossed a significant threshold.

According to a number of senior U.S. officials involved in the counterterrorism fight, the strike that killed Mehsud and other recent Predator drone activity in Pakistan's tribal areas indicate that the relationship with a once shaky ally in the war on terror has turned the corner in recent months.

U.S. officials and commanders had been frustrated until recently that Pakistan was not ready to make the leap and share intelligence on where some local Taliban commanders were located, impeding American efforts to eliminate them.

But the Pakistani government appears to be getting serious about counterterrorism, senior officials tell FOX News, suggesting that they more fully perceive the dangers they face from homegrown threats — and are allowing the gloves to come off to deal with them.

A senior U.S. counterterrorism official told FOX News, "There is a strong correlation between our growing knowledge of the Al Qaeda leadership and other terrorist groups (the Taliban) and the high number of commanders being taken off the battlefield."

Mehsud unleashed a fearsome campaign of suicide attacks and assassinations that made him the country's most-wanted man before he was killed in a U.S. airstrike, according to an aide to the former Taliban chief.

The U.S. put a $5 million bounty on his head in March. Increasingly, American missiles fired by unmanned drones have focused on Mehsud-related targets. U.S. officials believe Usama bin Laden's son, Saad bin Laden, was killed in a U.S. airstrike in Pakistan earlier this year.

While Mehsud's demise would be a major boost to Pakistani and U.S. efforts to eradicate the Taliban and Al Qaeda, it won't necessarily deal a definitive blow because he has deputies who could take his place.

Already, Taliban commanders were meeting Friday in a shura, or council, in the lawless tribal area of South Waziristan to choose his successor, according to intelligence and militant officials who spoke on condition of anonymity because of the sensitivity of the matter. It was unclear when they would reach a decision.

Considered by Pakistan to be its top internal threat, Mehsud had Al Qaeda connections and was suspected in the assassination of former Prime Minister Benazir Bhutto.

Pakistani and U.S. intelligence officials said the CIA was behind the strike Wednesday that killed Mehsud. All spoke on condition of anonymity because of the sensitivity of the matter.

Pakistan publicly opposes the missile strikes, saying they anger local tribes and make it harder for the army to operate. Still, many analysts suspect the two countries have a secret deal allowing them.

In June, Pakistan said it was launching an operation against Mehsud in South Waziristan. But although airstrikes began, the offensive never went full-scale. In the meantime, the U.S. missile strikes continued, increasingly targeting Mehsud and raising speculation that the Pakistanis were hoping — or even coordinating with — the Americans to kill Mehsud first.

FOX News' Jennifer Griffin, Catherine Herridge and the Associated Press contributed to this report.