Hadi delivered a televised speech on late Monday promising to eradicate extremism.
"The war on terror will continue no matter the sacrifices," he vowed.
For security reasons the military parade, attended by high-ranking officers and other dignitaries, was held at the Faculty of Aviation and Air Defense.
"We will not let terrorists intimidate our military. We will continue to fight evil … until our land is free," Chief of Staff Maj. Gen. Ahmed Ali Ashwal said in a speech.
On May 22, 1990, the Republic of Yemen was born, uniting the People's Democratic Republic of Yemen and the Yemen Arab Republic.