The Bush administration is considering multiple avenues to convince North Korea (search) to put down its nukes, and may impose a blockade on the nation to elicit compliance.

Plans range from establishing an economic embargo to interdicting North Korean ships. A possible blockade would prevent nuclear material from reaching rogue countries or terrorist groups.

White House aides are taking issue with a New York Times report that suggests the administration has come to the realization it can't end North Korea's nuclear program and is instead focusing on keeping the North Koreans from selling nuclear materials or technology.

Deputy Press Secretary Scott McClellan said the administration is equally concerned about North Korea's possession of nuclear weapons as well as its potential transfer of material.

North Korea is producing plutonium for nuclear weapons and is threatening to build bombs in what experts say is a form of blackmail against the United States in order to get more food and economic aid.

North Korea denies that it is a state-sponsor of terrorism, a designation by the State Department that prevents it from receiving U.S. aid or World Bank loans (search).

During talks last month among the United States, North Korea and China, the U.S. sought a peaceful remedy to the nuclear issue. North Korea, however, offered what it called a "bold proposal" to settle the dispute -- threatening to use or export the weapons if it doesn't get more aid.

President Bush received a briefing this weekend at his ranch by Assistant Secretary of State James Kelly, who conducted the three-way talks.

Kim Myong Chol (search), an alleged spokesman for North Korea, told Australian television that North Korea has a minimum of 100 nuclear warheads -- and as many as 300 -- all locked on American cities. Kim claimed that if the United States imposes a blockade or additional economic sanctions on North Korea, it will use its weapons against the United States.

Defense Secretary Donald Rumsfeld said Sunday that the United States has no military plans against the North, though he acknowledged that the administration hasn't ruled it out and there is always a backup plan for military action sitting on the shelf at the Pentagon. But, Rumsfeld said, diplomacy is the first line of defense.

"I can't believe they said they have 100 nuclear weapons. They certainly have a lot of weapons that could strike U.S. forces in the demilitarized zone but they most certainly do not have hundreds of nuclear weapons," Rumsfeld told Fox News Sunday

Secretary of State Colin Powell insisted the Bush administration's long-term goal is to force North Korea to dismantle all of its nuclear weapons and programs.

"We will not be blackmailed. We will not be intimidated," Powell said, adding, "North Korea is a master of saying all we have to do is keep threatening and throwing tantrums to get their way.  This time it is not going to work."

Powell said North Korea will not get any financial or food aid until it curbs its appetite for nuclear weapons.

Fox News' Kelly Wright contributed to this report.