(CNN)-- US Secretary of State Marco Rubio said that Iran is "not serious about talks" during his opening speech at the ASEAN foreign ministers' meeting Wednesday in Manila, Philippines.

Rubio said: "The United States is always committed to diplomacy. We are always open and ready to engage in dialogue, negotiation, and resolving differences. The problem we currently face (with Iran) is that they are not serious about talks. If they are serious, we are serious too. If they are not, we will do what is necessary to protect our interests and the interests of our allies."

Rubio warned of creating a "dangerous precedent" by allowing Iran to control the Strait of Hormuz, noting that they "do not have, under any existing legal mechanism, the right to control traffic through this international waterway," stressing that "the fundamental principle of freedom of navigation" is at stake.

He explained: "If this principle is threatened, I believe the global economy will be threatened, as well as the rules that have underpinned international trade for 150 years."

It is noted that the Strait of Hormuz was fully open to free and safe passage before the United States and Israel launched an attack on Iran in February at the start of the conflict. Iran considers its control of this waterway its most important bargaining chip in negotiations, and has repeatedly fired in recent weeks at ships it says did not communicate with Iranian authorities before transit.