“As service members, we must embody the values and ideals of the nation,” said the statement issued by the Joint Chiefs of Staff (JCS).
“We support and defend the constitution. Any act to disrupt the constitutional process is not only against our traditions, values and oath; it is against the law.”
Amid intense anxiety ahead of next weeks’ inauguration and fears of a repeat of the violence and chaos that reverberated across the world, reports said the uniformed leadership felt obliged to issue the statement and comment on live events, something it generally seeks to avoid doing.
The situation has been made even more tense by the determination of Democrats to oust Donald Trump before he completes his term, even though he has days to go. On Wednesday, the House is due to vote on a move to impeach him for the second time.
They and others have accused Mr Trump of inciting what many have termed an “insurrection”, most obviously during a speech to supporters in Washington DC shortly before hundreds of people stormed into the Capitol.
They were seeking to stop the certification of electoral votes cast for Mr Biden, having been persuaded by Mr Trump and others that the election was rigged. There is no evidence to support any electoral fraud.
The statement was first reported by CNN, which said Gen Mark Milley, the 20th Chairman of the Joint Chiefs of Staff, and the nation's highest-ranking military officer, issued it along with each of the top commanders of the different branches of the military.
“We witnessed actions inside the Capitol building that were inconsistent with the rule of law,” the statement added.
“The rights of freedom of speech and assembly do not give anyone the right to resort to violence, sedition and insurrection.”
The statement came as the House was due to vote on a measure calling for Mr Trump to be removed from office through the 25th amendment of the constitution.
House Democrats also plan to vote on Wednesday, to impeach Mr Trump, charging him with “incitement of insurrection”.
If the vote goes ahead, Mr Trump would the first president to be impeached twice.
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