A delay in the diplomatic process to end the US-Iran war can be explained by a lack of trust, Washington's contradictory positions and Israel's attacks on Lebanon, Iran's Foreign Ministry Spokesperson Esmaeil Baghaei said on Monday.

"Negotiations have started amid severe suspicion and mistrust, and the exchange of messages is taking place in this atmosphere," Baghaei said.

"The other party is constantly changing its views and putting forward new or contradictory demands (...) it is natural that this situation will prolong negotiations," he said, adding that Teheran viewed Israeli actions in the region, including in Lebanon, as inseparable from the US.

On Sunday, state media quoted top negotiator Mohammad Baqer Qalibaf as saying that Iran will not accept any agreement ending its conflict with the US unless there is certainty that the Iranian people's rights are secured.

"There is no trust in the enemy's words and promises. Our only criterion is to achieve tangible results before we fulfill our commitments in return," he added after taking an oath as the re-elected speaker of parliament alongside its presidium.