"We must be prepared at every moment for confrontation; right now, we are not even in a ceasefire (agreement); we are in a cessation of hostilities," said First Vice President Mohammad Reza Aref.
The fighting in June saw Israel bombard Iranian nuclear and military sites, as well as residential areas, killing more than 1,000 people, including senior commanders and nuclear scientists.
Iran retaliated with missile and drone strikes that killed dozens in Israel.
The United States announced a halt in fighting on June 24, two days after it joined the war by bombing Iranian nuclear facilities. But there was no agreement formalising the ceasefire, only an undeclared pause in hostilities.
On Sunday, Yahya Rahim Safavi, a military adviser to Iran's supreme leader Ayatollah Ali Khamenei, told Ira