The warship reinforcements -- designed to enhance the U.S. ability to patrol the vital Persian Gulf shipping lane and to counter a threat posed by Iranian naval mines - is part of the Obama administration's "two track" policy against Iran, senior administration officials told The New York Times.
The policy combines negotiations with new sanctions aimed at Iran's oil revenues and increased military pressure.
"The message to Iran is, 'Don't even think about it,'" a senior Defense Department official told the newspaper.
"Don't even think about closing the strait. We'll clear the mines. Don't even think about sending your fast boats out to harass our vessels or commercial shipping. We'll put them on the bottom of the gulf," the official said.
Another senior administration official told the newspaper last week, "When the president says there are other options on the table beyond negotiations, he means it."
The proposed Iranian legislation calls for Tehran's military to block any oil tanker heading through the narrow, strategically important strait toward countries no longer buying Iranian crude because of the European Union embargo, which took effect Sunday.
The legislation would be "an answer to the European Union's oil sanctions against the Islamic Republic of Iran," Ibrahim Agha-Mohammadi, a member of the Parliament's National Security and Foreign Policy Committee, was quoted by Iran's official Islamic Republic News Agency as saying.
It was unclear whether the legislation would pass the Parliament.
U.S. Joint Chiefs of Staff Chairman Gen. Martin Dempsey has said Iran's military is capable of temporarily closing the strait.
The Obama administration has warned any disruption would constitute a "red line" that would provoke a swift U.S. response.
"Any disruption will not be tolerated," a spokeswoman for the U.S. Navy's Fifth Fleet, which patrols the strait, warned in December, when Iran first spoke of shutting down the sea passage in response to the then-proposed sanctions on Iran's oil exports.
About 20 percent of the world's oil passes through the strait, which includes Iranian territorial waters that ships pass through under transit passage provisions of the U.N. Convention on the Law of the Sea.
The European embargo, along with new U.S. restrictions that took effect Friday, are intended to penalize Iran for refusing to suspend all uranium enrichment.
Western nations and Israel suspect the enrichment program is aimed at creating the ability to make nuclear weapons, which Iran denies.
A new round of low-level technical talks over Iran's nuclear program were to begin in Turkey Tuesday, two weeks after talks in Moscow ended with Iran and the five permanent members of the U.N. Security Council plus Germany acknowledging they were far apart from a possible deal.