Aboard the USS John C. Stennis ? From an aircraft carrier in the Persian Gulf, Vice President Dick Cheney warned Iran on Friday that the U.S. and its allies will keep it from restricting sea traffic as well as from developing nuclear weapons.

“We’ll keep the sea lanes open,” Cheney said from the hangar deck of the USS John C. Stennis as it steamed about 150 miles from the Iranian coast.

Cheney is touring the Middle East asking Arab allies to do more to help Iraq and to curb Iran’s growing power in the region. With Iraq in turmoil, both Iran and Saudi Arabia are maneuvering to see who can help fill the leadership vacuum.

The vice president made clear the United States’ intentions on the rivalry. “We’ll stand with others to prevent Iran from gaining nuclear weapons and dominating this region,” he said.

Cheney will make a fence-mending visit today to Saudi Arabia.

The oil-rich kingdom, long a key American ally in the Middle East, recently has been shunning the U.S.-supported government of Iraqi Prime Minister Nouri al-Maliki, suggesting he is too close to Iran.

Roughly a quarter of the world’s oil supplies pass through the narrow Straits of Hormuz connecting the Persian Gulf with the open waters of the Arabian Sea. Iran controls the eastern side of the straits.

With two U.S. carrier groups now in the region, the vice president declared: “We’re sending clear messages to friends and adversaries alike. We’ll keep the sea lanes open.”

The carrier was in the Gulf about 20 miles off Abu Dhabi in the United Arab Emirates. Cheney is spending time there after a two-day tour of Iraq.

Standing in front of five F/A-18 Super Hornet fighters and a huge American flag in the cavernous hangar deck – one flight below the carrier’s flight deck – Cheney sounded a hard line both on holding firm in Iraq and confronting Iran if necessary.

Just more than four years after President Bush stood on another aircraft carrier beneath a “Mission Accomplished” banner and declared an end to major combat, Cheney had a far more subdued message.

“We want to complete the mission, get it done right, and return with honor,” he told Stennis crew members.

Officials said that between 3,500 and 4,000 of the carrier’s 5,000 sailors and Marines stood in sweltering heat – hovering above 100 degrees – to hear Cheney speak.

“It’s not easy to serve in this part of the world. It’s a place of tension and many conflicts,” Cheney said.