U.S. President Barack Obama says the world is united in its response to Iran, leaving the country "more isolated than ever" and its leaders facing "crippling" sanctions.
The president said in an address to the nation Tuesday that he will not rule out any option for preventing Iran from obtaining a nuclear weapon, but that the issue can be resolved peacefully.
"But a peaceful resolution of this issue is still possible, and far better, and if Iran changes course and meets its obligations, it can rejoin the community of nations."
The president said the pressure on Iran will continue as long as it fails to live up to its responsibilities.
The United States and other Western nations have stepped up a campaign of sanctions against Iran, which they accuse of trying to develop a nuclear weapon. Iran denies the charge.
The sanctions include a ban on Iranian oil imports and measures targeting the country's banking system. The United Nations has also imposed four rounds of sanctions against Iran.
Iran has threatened to respond to new sanctions by closing the Strait of Hormuz, a vital pathway for global oil supplies. The United States has warned it will not tolerate such a move.
Iranian officials said Tuesday the latest Western sanctions will not work, and could even benefit Iran by leading to higher prices for Iranian crude.