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While state and national leaders are thankful Osama bin Laden is dead and acknowledged Pakistan’s assistance in the fight against al-Qaeda Monday, they also questioned whether bin Laden had a support system within the country that allowed him to remain hidden for so long.

The contradicting messages emphasize the problem between the two countries – Washington needs Islamabad’s partnership but is unable to trust its ally completely. The covert operation that saw the end of bin Laden was done without notifying Pakistan and, although drone strikes are commonplace, it would seem a raid by ground troops is in defiance of Pakistan’s wishes to not let foreign troops on its soil.

President Barack Obama’s top counter-terrorism adviser John Brennan said the government worried Pakistan would call upon its fighter jets while U.S. special forces flying in two Chinook helicopters got closer to their destination in Abbottabad, which is host to thousands of Pakistani troops.

Had a clash occurred between the two allies’ forces, Brennan said, a contingency plan had been created, though he would not give details. Relations between the U.S. and Pakistan were already strained after a CIA operative shot and killed two Pakistanis.

Although Pakistan did not object to the killing of the al-Qaeda leader, many questions remain as to how a man who evaded U.S. intelligence for more than a decade could have found asylum in a compound located so close to a major military base without anyone discovering his whereabouts.

Thankful for the help Pakistan did offer U.S. forces in the fight against terrorism, Brennan said he believes it is “inconceivable” bin Laden did not receive help from a support network inside the country. He would not reject outright that it could have been “official” in nature and said U.S. officials had already begun discussing the oddity with Pakistan.

The three-story compound in Abbottabad – about 35 miles from the country’s capital city, Islamabad – was custom-built for bin Laden sometime in 2005, according to U.S. officials.

Prominent U.S. lawmakers sounded off on the issue with mixed opinions.

Sen. Carl Levin, D-Mich., chairman of the Armed Services Committee, had no reservations and spoke forthright, saying to reporters that Pakistan’s military and intelligence services “have a lot of explaining to do,” he told reporters.

“The Pakistani army and intelligence have a lot of questions to answer, given the location, the length of time and the apparent fact that … this facility was actually built for bin Laden,” Levin said.

Secretary of State Hilary Clinton, on the other hand, said Pakistan “helped lead us to bin Laden and the compound in which he was hiding” and described the country as having “contributed greatly” to Washington’s fight against al-Qaeda.

Although the official announcement from the president came around 10:30 p.m. Sunday, rumors were already circulating around social networking sites and some have credited a U.S. government staffer with breaking the news an hour before Obama’s televised address.

Former Secretary of Defense Donald Rumsfeld’s Chief of Staff Keith Urbahn is widely accredited with being the first person to announce bin Laden’s death in a tweet around 9:30 p.m.

“So I’m told by a reputable person they have killed Osama bin Laden. Hot damn,” Urbahn’s tweet said.

After Urbahn’s announcement, Twitter activity increased until reaching its climax at more than 5,000 tweets per second around 10 p.m, still 30 minutes before Obama went to television, according to information Twitter released to its followers.

Still, according to University of Wisconsin professor Dietram Scheufele, the first tweet about the operation to take down bin Laden came even earlier from a man in Pakistan who alerted his followers: “Helicopter hovering above Abbottabad at 1 a.m. (is a rare event).”

The man, 33-year-old Sohaib Athar, then began to live tweet his observations in real time while U.S. forces continued with their assault, although he had no idea the helicopters were American or that the compound belonged to bin Laden.

“It may have been one of the first covert military operations that have been tweeted live,” Scheufele said.