Jonathan and Diana Toebbe pleaded guilty last month in the espionage case, but until now the identity of the nation they had approached had remained publicly undisclosed.

Moscow’s purchase of millions of shells and rockets from North Korea is a sign that global sanctions have hampered the Russian military’s supply lines.

Moscow has run a yearslong operation to blame Ukraine for its own 2016 election interference. Republicans have used similar talking points to defend President Trump in impeachment proceedings.

Surveillance video provided a dramatic portrait of action outside the al-Baghdadi compound, but could not show what happened in an underground tunnel where the ISIS leader died. For that, Mr. Trump...

Officials said Russia was planning a fake video showing an attack by Ukrainians on Russian territory or Russian speakers in eastern Ukraine.

Targeting assistance is part of a classified effort by the Biden administration to provide real-time battlefield intelligence to Ukraine.

They say they have indications that the $700 million, 459-foot yacht, which is in dry dock in Italy, is associated with the Russian president, backing an earlier claim by a former crew member.

The acting defense secretary ordered the spy agency to appoint Michael Ellis, who has been accused of having a hand in one of the Trump administration’s most contentious legal decisions.

An unusual email from the agency’s counterintelligence chief also warned retired officers to carefully weigh their comments on television, social media and podcasts.

A story about protesters burning Bibles drew condemnation from conservatives. It now appears to have been wildly exaggerated — and the first viral hit in Russia’s 2020 disinformation campaign.

Washington and its allies are scouring Central Europe and the world to get Ukraine the weapons it needs for the next phase of the war.

The FBI has joined the investigation into how a group of militants thought to be Islamists killed four American soldiers in Niger two weeks ago, a move that comes as U.S. officials face criticism...

The moves prompted accusations that President Trump’s allies were disclosing the information for his political benefit.

The attorney general has suggested that the Justice Department review of the Russia investigation has uncovered “troubling” findings without going into details.

American officials in China, Cuba and Russia say U.S. agencies are concealing the true extent of the episodes, leaving colleagues vulnerable to hostile actions abroad.

The Russian president has rejected requests from commanders in the field that they be allowed to retreat from Kherson, a vital city in Ukraine’s south.

To independent booksellers, the enormous chain was once a threat. Now it’s vital to their survival. And it’s doing well.

Authorities say Jack Teixeira, a 21-year-old member of the Massachusetts Air National Guard, posted sensitive materials in an online chat group.

The intelligence wars over vaccine research have intensified as China and Russia expand their efforts to steal American work at both research institutes and companies.

Intelligence officials have told the White House for weeks that China has vastly understated the spread of the coronavirus and the damage the pandemic has done.

A Saudi operative’s comments to a royal aide after the killing of the journalist Jamal Khashoggi is among the strongest evidence yet tying Crown Prince Mohammed bin Salman to his death.

President Volodymyr Zelensky is set to address Congress on Wednesday. NATO will discuss stepping up defenses. Mr. Zelensky urged more leaders to visit Kyiv after three prime ministers came to the...

Declassified U.S. intelligence accuses Moscow of pushing propaganda through alternative websites as Russia refines techniques used in 2016.

President Trump shrugged off the warning from the intelligence agencies, officials said.

The incident comes less than a week after a U.S. fighter jet brought down a Chinese spy balloon over the Atlantic during a diplomatic crisis.

The new intelligence chief wanted a briefer with experience and an apolitical record. She chose Morgan Muir, perhaps the first time a former White House briefer has returned to the post.

Yevgeny Prigozhin, the head of Wagner, may have believed he had support in Russia’s military.

The moves prompted accusations that President Trump’s allies were disclosing the information for his political benefit.

The director of national intelligence is said to be planning more disclosures of intelligence that undermines the Russia investigation.

Legislation backed by Chuck Schumer, the Senate majority leader, would create a review board to declassify documents related to unidentified aerial phenomena across the government.

A new government report is likely to fuel theories about unexplained aerial phenomena.

American officials said they were not aware of the plan ahead of time for the attack that killed Daria Dugina and that they had admonished Ukraine over it.

Counterintelligence officials said in a top secret cable to all stations and bases around the world that too many of the people it recruits from other countries to spy for the U.S. are being lost.

With an explosion heard across Kabul, Americans destroyed the base so its contents would not fall to the Taliban.

The disinformation campaign includes claims that NATO and Ukrainian forces are preparing to attack Russian speakers in Ukraine.

A Saudi operative’s comments to a royal aide after the killing of the journalist Jamal Khashoggi is among the strongest evidence yet tying Crown Prince Mohammed bin Salman to his death.

President Donald J. Trump’s interests during classified briefings have a new resonance amid the Justice Department’s criminal investigation into his handling of sensitive documents.

Dmitri Muratov was on a train preparing to leave Moscow at the time of the attack, which caused chemical burns to his eyes.

The information has fueled doubts in the United States that Iran, a longtime supporter of the Palestinian militant group, played a direct role in planning the assault in Israel.

Defense Secretary Jim Mattis is headed to Asia this week as the first member of Donald Trump’s cabinet to venture abroad amid the administration’s tumultuous start, seeking to reassure jittery allies...

A new report concedes that much about the observed phenomena remains difficult to explain, including their acceleration, as well as ability to change direction and submerge.

Jonathan and Diana Toebbe seemed like an ordinary suburban couple, but the F.B.I. said they were would-be spies — and sloppy ones.

Administration officials were determined to draft a response that would impose real costs on Moscow, as many previous rounds of sanctions have been shrugged off.

American intelligence officials had previously tried to extract the source from Russia in 2016, but the informant had initially refused.

The assessment, which the agency has moderate confidence in, buttresses earlier findings that the Russian president supports President Trump’s re-election.

Stacey A. Dixon is currently the deputy director of the Defense Department’s National Geospatial-Intelligence Agency.

The whistle-blower, a C.I.A. officer detailed to the White House at one point, first expressed his concerns anonymously to the agency’s top lawyer.

Forget space aliens or hypersonic technology; classified assessments show that many episodes have ordinary explanations.

Morgan Muir, who had led Mr. Biden’s first briefings in the early days of the administration, will oversee the assembly of the written President’s Daily Brief, among other responsibilities.

The spy agency does not believe its Russia informants have been killed, but sources have gone largely dormant amid heightened scrutiny and rising threats.

For weeks, the director of national intelligence has taken over a job usually done by an intelligence officer.

Under federal law, Richard Grenell, the new acting director of national intelligence, may be able to serve only a few weeks unless the president nominates someone to take on the job permanently.

William J. Burns, a veteran diplomat, has vowed to rebuild morale at the C.I.A. after it deteriorated during the Trump administration and to intensify its spying on China.