Lawmakers in the United States are taking a closer look at energy security, an issue that has been pushed to the forefront by a series of recent events threatening the global supply of crude oil. Energy security was the topic of hearings in both houses of Congress this week.

Assistant Energy Secretary Karen Harbert, in her testimony, listed several reasons why the Bush administration has become concerned about energy security.

"The world's energy depends on a few countries. Obviously, record high oil prices. Resources that are located in places that are geographically hard to reach, geologically hard to develop, politically unstable and unfriendly to new investment," she said.

In the Senate, Senator Richard Lugar said there is strong bipartisan interest among his colleagues in making sure the United States has a secure supply of energy. He said Moscow's decision earlier this year to cut off the supply of gas to Ukraine, in what was widely seen as political blackmail, clearly showed energy in tight markets could become a powerful political weapon.

"Somebody that shuts off the tap to Ukraine, for example, accomplishes something that you do not have to send aircraft over or tanks, or what have you, to do. You can obliterate a country this way. And that is one reason that we are talking about this, because we said as these things start to close in, the knives get sharper and the elbows likewise, or people in a strategic position decide to use this aggressively against others, maybe against us," he said.

At a House of Representatives' hearing on the subject, Congressman Stephen Lynch listed other examples of potential global problems affecting the supply of oil to the United States.

"Iran, for example, the second-largest producer within the Organization of Petroleum Exporting Countries, has repeatedly issued thinly-veiled supply disruption threats in response to U.S.-led efforts to curb that country's uranium enrichment program. In addition, Venezuela's President Hugo Chavez, whose country is the United States' fifth largest source of imports, has similarly asserted the possibility of retaliatory oil-related actions stemming from his opposition to U.S. policy," he said.

Another problem country lawmakers pointed to is Nigeria, a major supplier of oil for the United States, where violence has disrupted production in recent month.

The State Department's Paul Simons said Washington can deal with temporary disruptions in oil supply by using the country's emergency reserves.

"I think the option that we try to keep most available and most ready to use is our coordinated use of our strategic stocks, and, as you will recall, during Hurricanes Katrina and Rita last fall, we were able to work with the 26 members of the International Energy Agency, and, within 24 hours, we agreed to release 60 million barrels of oil to meet that supply disruption that was actually caused by a natural occurrence here on U.S. shores," he said.

Much of the 21 million barrels of oil the United States consumes each day comes from other countries.

"We produce about nine million barrels a day, roughly. We import about 12 million barrels a day," said Jason Grumet, executive director of the National Commission on Energy Policy, an independent group made up of representatives from government, academia and industry. He said because the United States imports so much of the oil it needs, it cannot afford to ignore the world's trouble spots.

"It leads one to emotionally desire to basically take our marbles and go home, get away from these guys. The problem is, we have three percent of the world's marbles, and we use 25 percent of annual oil production. So, the notion that we can somehow isolate ourselves from this global dynamic is a vestige of a path that does not really exist," he said.

Energy security is topping the agenda for the G-8 summit of the world's seven most industrialized countries and Russia to be held in St. Petersburg in July.

Daniel Yergin, chairman of the independent consulting firm, Cambridge Energy Research Associates, told Congress the G-8 discussion will be a good start to global energy debate.