President Bush says a variety of global forces are to blame for crude-oil prices topping $70 a barrel.

"There is tight supply worldwide, and we have got increasing demand from countries like India and China, which means that, any disruption in supply, or perceived disruption of supply, is going to cause the price of crude to go up, and that affects the price of gasoline," he said.

The president says prices are also up on increasing domestic demand, as Americans are driving more, now that the cold winter weather is ending, and because states are switching their fuel-mix to a warmer-weather blend.

"The combination of these creates higher gasoline prices, and I am concerned about higher gasoline prices. I am concerned about what it means for working families and small business, and I am also mindful that the government has the responsibility to make sure that we watch very carefully, and investigate possible price-gouging, and we will do just that," added President Bush.

The price of crude hit a new record, eclipsing the previous mark set last August, when Hurricane Katrina disrupted production in the Gulf of Mexico.

Analysts blame some of the current price hikes on worries about global instability in oil-producing regions, including ethnic violence in Nigeria and the dispute over Iran enriching uranium.

Tehran says its nuclear program is meant to produce electricity. President Bush says the world's fourth-largest oil producer is secretly developing a nuclear-weapons program.

Taking questions from reporters in the White House Rose Garden, Mr. Bush said he will discuss the issue in talks Thursday at the White House with Chinese President Hu Jintao.

"We want to solve this issue diplomatically, and we are working hard to do so," he said. "The best way to do so is therefore to be a united effort with countries, who recognize the danger of Iran having a nuclear weapon."

The International Atomic Energy Agency reports back to the U.N. Security Council about Iran next week. If the country does not stop enriching uranium, the Bush administration is expected to call for economic sanctions.

Iran says no amount of pressure will force it to abandon its nuclear program. Tehran's Foreign Ministry dismissed talks among the United States, Britain, France, Russia, China and Germany, saying their Moscow meeting is more important to the participants than it is to Iran.

White House officials say President Bush is skeptical about being able to resolve the dispute peacefully. Iranian President Mahmoud Ahmadinejad says any aggressor would regret attacking his country, because he says Iran has one of the world's most powerful armies.