WASHINGTON – The CIA and departments of Justice and Homeland Security have launched a high-level internal review of whether intelligence was mishandled prior to the Boston Marathon bombings, though President Obama and his top advisers said they have seen nothing to suggest counterterrorism agencies did anything wrong.

Obama told a White House news conference that the review would seek to answer whether “additional things could have been done” and that “might have prevented” the two bombings that killed three people and injured more than 260 on April 15.

“We want to go back and we want to review every step that was taken,” Obama said. “We want to leave no stone unturned.”

The House Homeland Security Committee has announced plans to hold hearings, and House Speaker John Boehner said other committees will do so, as well. The Senate Homeland Security Committee is also expected to hold hearings. Some lawmakers have expressed concerns that information about the older bombing suspect, Tamerlan Tsarnaev, wasn’t properly shared. Asked at the news conference if “our intelligence missed something” on the Boston bombers, Obama said flatly, “No.”

“Based on what I’ve seen so far, the FBI performed its duties, the Department of Homeland Security did what it was supposed to be doing,” Obama said. “But this is hard stuff.”

James Clapper, the director of national intelligence, “believes that every agency involved in collecting and sharing information prior to the attack took all the appropriate steps,” said his spokesman, Shawn Turner. “He also believes that it is prudent and appropriate for there to be an independent review of those steps to ensure that nothing was missed.”

Clapper advised Congress in a memo that Charles McCullough III, inspector general for the 17 intelligence agencies, will coordinate the review. The scope is still being worked out, but officials expect that it will last about 90 days.

The FBI opened what is called a “foreign police cooperation case” and interviewed Tamerlan Tsarnaev in 2011 after Russian authorities warned that he might have ties to extremist groups. The FBI found no radical links and therefore no basis to open a full investigation or obtain warrants to search Tsarnaev’s computer, officials said. But based on the same information from the Russians, the CIA put Tsarnaev and his mother on a general terrorism watch list before he traveled to Russia in January 2012.

Tsarnaev, who authorities believe was the mastermind behind the bombings, was killed during a shootout with police in Boston on April 19. His younger brother, Dzjokhar, was captured that night and is in custody at a federal prison medical facility in Massachusetts.

Some members of Congress have asked why U.S. Customs officials did not alert the FBI when Tamerlan Tsarnaev left the United States for Russia last year, or again six months later, when he landed back at John F. Kennedy International Airport in New York.

In each case, a customs official on New York’s Joint Terrorism Task Force received an alert about Tsarnaev’s travel. There is no evidence officials passed it on to FBI partners on the task force, authorities have said.

Lawmakers also have questioned why customs didn’t question Tsarnaev, given that the Russian government had told the FBI and CIA he might be a threat.

“In Boston, both the FBI and CIA were warned by the Russians about a radical Islamist in our midst,” Sen. Lindsey Graham, R-S.C., said in a statement. “Once enrolled in the system as a potential terror suspect, the older brother was able to travel back to Russia unimpeded by DHS or any of our intelligence agencies. Agencies were unable to coordinate the information they received,” he said.