EU foreign policy chief, Kaja Kallas, says she is preparing a fresh round of sanctions on Iran following recent foreign-backed riots in the country.
Authorities in Tehran say initially peaceful protests were hijacked by violent groups backed by the United States and Israel.
Many pro-Israel EU lawmakers support tougher measures against the Islamic Republic, though others are pushing back.
When Israel was committing genocide in Gaza, you didn't mind, but now you talk about human rights in Iran!
You see how hypocritical you are, and you are the military extremists.
You don't have to like what's happening in Iran, but it's a sovereign country.
Lubos Blaha, Slovakian MEP
Some legislators argue that Donald Trump and the hardliners around him are determined to trample international law in pursuit of geopolitical advantage.
Trump is the Hitler of the 21st century.
The US should be isolated, and we should not be helping them bomb Iran.
We should look at historic agreements that are being signed by Canada, for instance, with China.
That's the way forward.
Irene Montero, Spanish MEP
The West has already imposed sweeping economic sanctions on Iran over its civilian nuclear program, despite Tehran having fully complied with a 2015 nuclear deal before it was illegally abandoned by Trump.
Sanctions breed chaos.
Our double standards as well have been used against us as an argument when the US Israeli strikes killed Iranian civilians, this parliament failed to condemn.
The Israelis announced covert operations in Iran and we are not able to condemn.
Marc Botenga, Belgian MEP
During the recent riots in Iran, mosques, hospitals, schools, banks, power infrastructure and shops were attacked. Civilians were caught in the violence, along with security forces personnel.
How would the Western security forces react to the killing of 500 or more police officers? I don't think that would go down well in any Western country.
Nilufar Ashtari, Peace Activist
A number of lawmakers are now calling on Western governments to stop interfering in Iran's internal affairs.
In 1979 there was a revolution. Mossad tried to have a coup, but from outside, you actually prevent proper protests from taking place. Turkey and Saudi Arabia are trying to prevent an escalation. You should listen to them.
Tomasz Froelich, German MEP
Many independent security analysts say the West continues to greatly underestimate Iran's defensive capabilities, noting that only a fraction of those were revealed during last June's 12-day war.
They argue that diplomacy, rather than sanctions or military threat remains the most prudent way forward.