Mr Salvini said on Wednesday that the suspension of Gen Vannacci was “ridiculous”.
“The situation is ridiculous. How scared are they of the general? Long live freedom of thought and speech, long live the armed forces and the police,” he wrote on Twitter.
Gen Vannacci is also under investigation for alleged financial irregularities during his time as military attaché to the Italian embassy in Moscow in 2021-22.
He has denied any wrongdoing during his time in Moscow. The allegations of fraud and embezzlement were revealed earlier this week by the newspaper Corriere della Sera.
“I don’t discuss questions from the press about my service,” he said. “I am totally relaxed and will respond at the appropriate time.”
While his book has been lauded in some Right-wing circles in Italy, it has been condemned by members of the government.
Guido Crosetto, the defence minister and one of the founding members of Ms Meloni’s Brothers of Italy party, said that “the personal ramblings of a general” had discredited the armed forces.
Antonio Tajani, the foreign minister, said last year that the general should have shown more “prudence” before expressing such inflammatory opinions.
