(CNN)-- Iran's chief negotiator, Mohammad Baqer Qalibaf, emphasized in a statement released by the official Islamic Republic of Iran Broadcasting (IRIB) on Wednesday the need for Iran to continue defending itself while remaining open to diplomatic dialogue.

He added that Iran is engaged in a 'fundamental and existential' conflict with the United States.

Qalibaf, the speaker of the Iranian parliament, said: 'We have never welcomed war, and we do not welcome it now, but we must always be on alert for battle, ready to defend our national security and interests with our lives. At the same time, we must also use diplomacy and negotiations to advance and consolidate our national interests.'

Qalibaf warned that Iran 'has no justification to adhere to an agreement that does not benefit it' and that 'the armed forces have full freedom of action' to respond to any aggression.

Qalibaf called for preserving 'Iranian arrangements' in the Strait of Hormuz, which enable Iran to control the waterway, and accused the United States of 'trying to weaken these arrangements by force.' He insisted that 'our national security depends on maintaining' control of the strait.

Qalibaf also addressed Iranians living in the southern regions of the country, which are under constant air raids, saying: 'You are Iran's lifeline, and we will sacrifice our lives for you a thousand times.'