Rouhani was referring to the Kingdom of Bahrain, which Iranian officials in the past have referred to as the "14th province".
Javani, the deputy for the IRGC political bureau, was speaking at a rally marking the 40th anniversary of the Islamic Revolution, when the US-backed monarchy was overthrown and replaced in power by Islamic fundamentalists.
"Were this regime to make the awful mistake of trying to destroy Tel Aviv and Haifa, it would not succeed, but it would mean that they had celebrated their last Revolution Day".
In a speech at Tehran's Azadi (Freedom) square, Rouhani said USA efforts to isolate Iran would fail.
State TV showed large crowds defying frigid weather and carrying Iranian flags while chanting "Death to Israel, Death to America", trademark chants of the revolution.
Life-size replicas of Iranian-made cruise and ballistic missiles stood in a statement of defiance after the USA previous year reimposed sanctions following its withdrawal from a deal on Tehran´s nuclear programme.
The celebrations included several instance of muscle flexing, including the launch and test of new missiles, which would put Israel squarely within precise range of the Iranian armed forces.
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The state has played up this year's anniversary as 40 is symbolic of maturity in the Islamic tradition and the age at which Prophet Mohammed received revelations from God.
Iranians thronged streets across the country, many with portraits of Ayatollah Ruhollah Khomeini, the Shiite cleric who toppled the Shah in the historic Islamic uprising.
Prices of basic foodstuffs have soared since President Donald Trump withdrew Washington from the 2015 nuclear deal in May 2019.
"The Iranian people have and will have some economic difficulties [due to the sanctions] but we will overcome the problems by helping each other", Rouhani said in his address.
Israeli television reported last week that Israel has discovered a new ambitious precision missile factory being constructed by Iran in Syria together with the Syrian government and Lebanese terror group Hezbollah, after Israel bombed and destroyed a previous one.
The United States and its Arab allies have viewed Iran with great suspicion since the Islamic Revolution swept the Shah from power in 1979, fearing Khomeini's radical ideology would inspire Islamic militants across the Middle East.
Referring to Iran as "the Mother Land", Rouhani said that during the rule of "the traitor Qajar dynasty 205 years ago", large portions of lands were separated from Northern Iran and the caucuses.
A senior commander in Iran's Revolutionary Guards said Tehran would not withdraw forces from the region, dismissing USA calls for Iranian clout to be curbed.