"Iran has been, and will be, the main guardian of security and freedom of navigation in the Persian Gulf, the Strait of Hormuz and the Sea of Oman during history," said Rouhani, according to a presidential statement released on Tuesday.
Rouhani's remarks came hours after the UK proposed an Europe-led "maritime protection mission" to ensure the safety of cargo vessels passing through the Strait of Hormuz, where Iran seized the British oil tanker Stena Impero last week.
Speaking at a meeting with Iraq's Prime Minister Adil Abdul-Mahdi in Tehran on Monday night, the leader also said that Iran was "not willing to escalate tensions in the region and with other countries and will never initiate war", Efe news reported.
"We believe that the issues of the region should be resolved through dialogue, negotiation and cooperation between neighbours and regional countries," he added.
Tensions in the Persian Gulf escalated last Friday after Iran's Revolutionary Guard Corps seized the Stena Impero.
While Iranian authorities said the tanker was not complying with international maritime rules, the UK described the seizure as illegal.
UK Foreign Secretary Jeremy Hunt said on Monday that he spoke to his counterparts in several EU countries as well as in Iran, Oman and the US and said the Department of Transport raised the security level for British-flagged shipping to Level 3, "advising against all passage in Iranian waters and, for the moment, in the entire Strait of Hormuz".
He was also seeking the creation of the maritime protection mission to ensure free and safe navigation in the region.
"If Iran continues on this dangerous path, they must accept the price will be a larger Western military presence in the waters along their coastline, not because we wish to increase tensions but simply because freedom of navigation is a principle which Britain and its allies will always defend," Hunt said.
( With inputs from IANS )