President Donald Trump said he did not give many congressional leaders advance notice of the raid that killed ISIS leader Abu Bakr al-Baghdadi on Saturday because he was afraid of "leaks," he told reporters at a Sunday news conference.

"We notified some, others are being notified now as I speak," Trump said. "We were going to notify them last night but we decided not to do that because Washington leaks like nothing I've ever seen before. There has no country in the world that leaks like we do. Washington is a leaking machine."

Trump said the members of Congress he informed ahead of the raid were North Carolina Sen. Richard Burr and South Carolina Sen. Lindsey Graham, both Republicans. Burr, the chairman of the Senate Intelligence Committee, is on what is known as the "Gang of Eight" for intelligence-related matters: Senate and House leaders from both parties and the chairman and ranking members of the House and Senate intelligence committees.

Trump said only "very few people" were made aware of the raid, naming top officials in his administration and later Burr and Graham.

"A leak could have caused the death of all of them," he said.

Asked later if he informed House Speaker Nancy Pelosi ahead of the raid, Trump said, "I did not do that," adding he "wanted to make sure" the mission was kept "secret."

"I don't want to have men or women lost," he said. "I don't want to have people lost."

In a Sunday statement, Pelosi expressed relief that no U.S. servicemembers were killed and said that al-Baghdadi's death was "significant, but the death of this ISIS leader does not mean the death of ISIS."

"The House must be briefed on this raid, which the Russians but not top Congressional Leadership were notified of in advance, and on the administration’s overall strategy in the region," Pelosi said. "Our military and allies deserve strong, smart and strategic leadership from Washington."

Trump said on Sunday that he notified Russia in advance that the U.S. was "going over an area where they had a lot of firepower" but not about the purpose of the raid.

"We spoke to the Russians. We told them we are coming in. They said, 'Thank you for telling us,'" he said. "We told them we thought they would be happy. They hate ISIS as much as we do. You know what ISIS has done to Russia. They did not know the mission but they knew we were going over an area where they had a lot of firepower."

Speaking on ABC's "This Week," House Intelligence Chairman Adam Schiff, D-Calif., said he was not briefed on the raid before it was carried out.

The ISIS leader "was a blood-thirsty killer to the degree that he retained operational control of ISIS, Schiff said. "This is an operational success, this is a symbolic victory. He had the blood of thousands and thousands of people on his hands, including many Americans and American journalists. So, this a great day, a ruthless killer has been brought to Justice."

"In terms of notifying the Gang of 8, that wasn’t done," he added.

A spokesman for Senate Minority Leader Chuck Schumer, D-N.Y., told NBC News that he was not notified in advance.

“I look forward to receiving a briefing about this raid and the plan to deal with the escaped ISIS prisoners," Schumer said in a statement later on Sunday.

House Foreign Affairs Chairman Eliot Engel, D-N.Y., and House Armed Services Chairman Adam Smith, D-Wash., were also not made aware, two sources told NBC News. Engel and Smith are not members of the "Gang of Eight."

Smith’s office said it had reached out to the Defense Department to learn why there was not a pre- or post-strike call and why they had not received any information as of Sunday mid-morning.

"The Administration and Department officials must have open and continuous dialogue with congressional officials so we can fully understand the next steps and the long-term strategy for the region," Smith said in a statement.

"I am extremely troubled Trump notified only Republicans, but did not see fit to inform me or any Congressional Democrats of the operation," Engel said. "His implication that Speaker Pelosi, the elected representative third in line for the Presidency, cannot be trusted with sensitive information is tremendously problematic and insulting, and further politicizes foreign policy—especially when Trump has shown himself to be an untrustworthy guardian of our national security and sensitive intelligence information."

Rep. Tulsi Gabbard, D-Hawaii, said it was “unfortunate” that the administration didn’t notify Democrats.

"Whether you're a Democrat or Republican, working towards that objective of keeping the Americans safe and defeating terrorist groups like ISIS and Al Qaeda should always be at the forefront,” she said.

Graham, who spoke with reporters from the White House briefing room following Trump's press conference, said he did not have any answer on why Trump did not notify those Democrats of the raid.

"That's not my concern today," he said.

Speaking with "Fox News Sunday," Vice President Mike Pence did not directly answer repeated questions from host Chris Wallace on why Trump did not inform Pelosi of the raid, saying he did not think the idea that she would leak the information "was the implication at all."

"From the time we got actionable intelligence, the president's focus was on a successful mission and the safety of American troops," he said, adding that the administration "maintained the tightest possible security here."