Senate Republicans and Democrats said they hoped Clinton would testify on the Hill even though she is planning to step down from her Cabinet post.
In a letter that accompanied the transmission of the report to Capitol Hill, Clinton thanked the board for its "clear-eyed, serious look at serious systemic challenges" and said she accepted its 29 recommendations to improve security at high-threat embassies and consulates.
She said the department had begun to put in place some of the recommendations. They include increasing by several hundred the number of Marine guards stationed at diplomatic missions throughout the world; relying less on local security forces for protection at embassies, consulates and other offices; and increasing hiring and deployment of highly trained Diplomatic Security agents at at-risk posts.
Clinton agreed with the panel's finding that Congress must fully fund the State Department's security initiatives. The panel found that budget constraints in the past had led some management officials to emphasize savings over security, including rejecting numerous requests from the Benghazi mission and the embassy in Tripoli for enhanced protection.
House and Senate negotiators working on a defense bill agreed on Tuesday to fund 1,000 more Marines at embassy security worldwide.
The report singled out the Bureau of Diplomatic Security and the Bureau of Near East Affairs for criticism. It said there was a lack of cooperation and confusion over protection at the mission in Benghazi, a city in eastern Libya that was relatively lawless after the revolution that toppled Libyan leader Moammar Gadhafi.
But it broke little new ground about the timeline of the Benghazi attack. Killed were U.S. Ambassador Chris Stevens, information specialist Sean Smith, and former Navy SEALs Glen Doherty and Tyrone Woods — who were contractors working for the CIA. Stevens was the first U.S. ambassador killed since 1988.
The board determined that there had been no immediate, specific tactical warning of a potential attack on the 11th anniversary of Sept. 11, 2001. But the report said there had been several worrisome incidents before to the attack that should have set off warning bells.
It did confirm, though, that contrary to initial accounts, there was no protest outside the facility.
In the immediate aftermath of the attack, administration officials linked the attack to the spreading protests that had begun in Cairo earlier that day over an American-made, anti-Islamic film. Those comments came after evidence already pointed to a distinct militant attack in Benghazi.
U.N. Ambassador Susan Rice appeared on numerous TV talk shows the Sunday after the attack and used the administration talking points linking it to the film. An ensuing brouhaha in the heat of the presidential campaign eventually led her to withdraw her name from consideration to replace Clinton as secretary of state in President Barack Obama's second term.
Sen. Jim Inhofe, R-Okla., emerging from the Senate briefing on the report, kept up the congressional criticism of Rice.
"Now we all know she had knowledge. She knew what the truth was. It was a cover-up," he said.
While criticizing State Department management in Washington along with the local militia force and contract guards that the mission depended on for protection, the report said U.S. personnel on the ground in Benghazi "performed with courage and readiness to risk their lives to protect their colleagues in a near-impossible situation."
It said the response by Diplomatic Security agents on the scene and CIA operatives at a nearby compound that later came under attack itself had been "timely and appropriate" and absolved the military from any blame. "There was simply not enough time for armed U.S. military assets to have made a difference," it said.
The report also discounted speculation that officials in Washington had refused appeals for additional help after the attack had begun.
The report said the evacuation of the dead and wounded 12 hours after the initial attack was due to "exceptional U.S. government coordination and military response" that helped save the lives of two seriously wounded Americans.
Associated Press writers Donna Cassata and Kimberly Dozier contributed to this report.