Washington (CNN) - The United States is pressing Pakistani authorities for answers about how Osama bin Laden could have lived close to a major military base near Pakistan's capital without the government knowing, two senior U.S. officials said Wednesday.

The al Qaeda leader was living in a walled compound in Abbottabad, about 50 km (31 miles) north of Islamabad, when he was gunned down by American commandos in a pre-dawn raid Monday. The killing has left Pakistani officials facing sharp questions from Washington - and in some cases, from their own people - and exacerbated an already rocky relationship between the two nations.

A senior Pakistani intelligence official reacted angrily Wednesday to comments by CIA Director Leon Panetta, who told U.S. lawmakers in a closed-door session Tuesday that Pakistani officials were either "involved or incompetent" in bin Laden's case - and, "Neither is a good place to be."

The official, who did not want to be named, said his country had been generously sharing intelligence with its American counterparts.

"Of all people," the Pakistani official said, Panetta "knows how much we have been doing."

"What worse statement can come than that we heard from Panetta?" the official said. "I am afraid this statement is totally regrettable."

But the discovery of bin Laden, who was living in a three-story, walled home a short distance from a prestigious Pakistani military academy, has fueled calls by American lawmakers to re-examine the U.S.-Pakistani relationship.

(CNN) - Pictures taken shortly after the raid that killed al Qaeda leader Osama bin Laden show three men lying dead in pools of blood and the wreckage of a U.S. helicopter abandoned during the assault.

One of the dead men bears a family resemblance to bin Laden, but there was no confirmation of his identity. The al Qaeda leader's adult son was among those killed in Monday's attack by U.S. commandos, according to American officials.

The pictures were published Wednesday by Reuters. The news agency says they were taken by a Pakistani security official about an hour after U.S. forces left bin Laden's compound and that it is confident of the authenticity of the purchased images.

Abbottabad, Pakistan (CNN) - U.S. officials issued a revised version of the nighttime raid that killed the world's most-notorious terrorist, including additional details that revealed other options were on the table before settling on the assault.

The 40-minute raid early Monday in Pakistan left Osama bin Laden dead, along with four others in the complex that sits on a mountainous region near the capital.

Bin Laden was not armed during the raid, but he put up resistance when U.S. forces entered the compound, the White House said. Officials had earlier said that bin Laden was an active participant in the firefight, implying that he was armed and gave the U.S. Navy SEALs little choice but to shoot him down.

After the operation, U.S. forces departed with the al Qaeda leader's body, nearly 10 years after the September 11, 2001, terrorist attacks on the United States.

"It was a staggering undertaking and there was no one else, I believe, other than an American group of military warriors who could do it," U.S. Vice President Joe Biden said Tuesday. "And the world is a safer place today, not only for the American people but for all people."

Officials on Tuesday offered new details about the raid and clarified earlier accounts.