The comments by General Mohammad Ali Jafari to reporters mark the first acknowledgement that Ayatollah Ali Khamenei has imposed limits on the country's ballistic missile programme.
It also appears to be an effort by Iranian authorities to contrast its program, which they often describe as for defensive purposes, against those of countries like North Korea, which now uses its arsenal to threaten the United States.
That's caused concern for the U.S. and its allies, even as Iran's ballistic missile program was not included as part of the 2015 nuclear deal that Tehran struck with world powers.
Speaking on the sidelines of a conference in Tehran, Jafari told journalists that the capability of Iran's ballistic missiles is "enough for now." The Guard runs Iran's missile programme.
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"Today, the range of our missiles, as the policies of the Iran's supreme leader dictate, are limited to 2,000 kilometres, even though we are capable of increasing this range," he said.
However, Jafari said he didn't believe there would be any war between Iran and the US.
"They know that if they begin a war between Iran and the United States, they will definitely be the main losers and their victory will by no means be guaranteed," he said.
"Therefore, they won't start a war."
While keeping with the anti-American tone common in his speeches, Jafari's comments seemed to be timed to calm tension over Iran's missile programme.
Pyongyang also flew two powerful new midrange missiles over Japan, between threats to fire the same weapons toward Guam, a US Pacific territory and military hub.
The Trump administration already sanctioned Iran for test-firing a ballistic missile in February, with then- National Security Adviser Michael Flynn warning Tehran that Iran was "on notice."
President Donald Trump's recent refusal to re-certify the nuclear accord has sent the matter to the US Congress. On Thursday, the US House of Representatives voted to put new sanctions on Iran for its pursuit of long-range ballistic missiles, without derailing the deal.
To build its own programme, Tehran purchased North Korean missiles and technology, providing much-needed cash to heavily sanctioned Pyongyang.
The Gulf Arab nations surrounding Iran, while hosting American military bases, also fly sophisticated US fighter jets that Iranian forces can't match. The ballistic missiles provide leverage against them, as well as the US-made anti- missile batteries their neighbours have bought, according to Tytti Erasto, a researcher at the Stockholm International Peace Research Institute.
Meanwhile today, Iran broke ground at its Bushehr nuclear power plant for two more atomic reactors to generate electricity. State television quoted Ali Akbar Salehi, the head of the Atomic Energy Organisation of Iran, as saying the first new reactor would go online in seven years, while a third would be active in nine years.