By Christiane Jacke, Thomas Müller, Marc Kalpidis

Washington, D.C. (USA) - The opposition in the US parliament wants an investigation into a suspected government communications breach that apparently allowed a journalist to follow a group chat about a planned military attack in Yemen.

The minority leader of the Democrats in the Senate, Chuck Schumer (74), spoke of "amateurish behavior" on Platform X and called for a comprehensive investigation. The newspaper "The Hill" and the broadcaster ABC quoted him as saying that it was "one of the most incredible breaches" of military secrets that he had ever come across.

The group conversation between leading government representatives via the messenger app Signal is said to have been about the - still imminent - attack on the Houthi militia in Yemen. The editor-in-chief of the renowned US magazine "The Atlantic", Jeffrey Goldberg (59), was inadvertently included in the group according to his own account and later made the incident public. A spokesman for the National Security Council, Brian Hughes, confirmed that the chat was most likely authentic. He announced an internal review.

Democratic Senator and military expert Jack Reed (75) declared that "if this story is true, it represents one of the most egregious failures of operational security and common sense I have ever seen".

Military operations must be conducted with the utmost discretion and through authorized, secure lines of communication, he said, because American lives are at stake. "The negligence shown by President Trump's cabinet is astounding and dangerous. I will demand answers from the administration immediately."

There are usually strict rules on how the US government should handle confidential and top secret information relating to national security. This applies all the more to concrete plans for military operations abroad. According to the Atlantic, the Signal app is generally not approved by the US government for the exchange of confidential information.

In his article, Goldberg describes in detail the exchange between the participants in the chat - with exact times and original quotes. According to the article, both military tactics and political communication relating to the planned strike against the Houthi militia in Yemen were discussed. Goldberg listed Vice President J.D. Vance (40), Secretary of Defense Pete Hegseth (44), Secretary of State Marco Rubio (53) and other cabinet members and high-ranking government officials as group members.

In Goldberg's article, the sometimes informal tone of the chat protagonists in the military context is also striking.

The journalist wrote that Trump's National Security Advisor, Michael Waltz (51), who is said to have included him in the group, used emojis to signal approval and a fighting spirit: a clenched fist, a US flag and a flame symbol.

Particularly explosive: two hours before the attacks began on March 15, Hegseth himself is said to have provided detailed information on targets, weapon systems and the timing of the operation in a chat. Shortly afterwards, airstrikes actually began against positions of the Houthi militia in Yemen, which the USA had recently reclassified as a foreign terrorist organization.

Hegseth later vehemently denied the "Atlantic" report. "Nobody texted war plans," he replied to a reporter's question at the airport in Hawaii after landing.

The former TV presenter for the right-wing conservative Fox News channel denigrated Goldberg as a "deceitful and discredited so-called journalist" who had made it his profession to campaign against the government and repeatedly spread false reports.

Hegseth's invective contradicted the statements of Security Council spokesperson Hughes, who had described the chat as most likely authentic. Trump himself had previously stated that he had not heard of the group chat, but that he was "not a big fan" of "Atlantic" magazine anyway.