"We have had a pattern of increasing the number of coalition forces during periods when there was an expectation that the insurgents and terrorists would like to try to disrupt the political process," Rumsfeld told Pentagon reporters.

Rumsfeld and Gen. Peter Pace, chairman of the Joint Chiefs of Staff, said they expect insurgents to expand their attacks as the elections approach, but would not say exactly how they plan to protect U.S. soldiers from the growing number of roadside bombs.

"We'll decide what we're going to do about December as we go along, but it would not be a surprise to me that the commanders would want to have some sort of an overlap there" between arriving and departing units, Rumsfeld said.

U.S. troop levels rose to a peak of 161,000 before the October 15 election on the new constitution, but dipped to 158,000 as of Tuesday. There were 159,000 U.S. troops in Iraq for the January elections.

Rumsfeld also defended the government's decision not to permit United Nations human rights investigators to meet with terror suspects detained at Guantanamo Bay. Three U.N. experts were given permission to visit the facilities in Cuba but said they won't go if they could not interview prisoners.

Rumsfeld said it was not appropriate to give U.N. investigators the same extensive access that has been granted to officials of the International Committee of the Red Cross.

"There has to be a limit to how one does that," Rumsfeld said, adding that the government does not want to increase the number of organizations that have extensive access to the detainees. He said the decision not to provide full access to the U.N. officials was made not by the Pentagon but by the U.S. government.

Rumsfeld and Pace talked at length about the deadly homemade bombs -- called improvised explosive devices -- that have become a growing threat in Iraq, including killing seven service members in three separate attacks Monday.

January and October were two of the deadliest months in Iraq, they said, because elections were held then, and the insurgents are trying to prevent the Iraqi people from participating in the political process.

Pace said U.S. forces are still finding an enormous amount of explosives in Iraq. The Pentagon and its commanders, he said, are working to find the best technologies and tactics to protect the troops, including better armor and improved battlefield operations.

He said that while the number of IED attacks has risen, the number of casualties per effective IED attack is going down. As of Tuesday, the U.S. military death toll for October was at least 93, bringing the total number of military deaths to at least 2,026 since the war in Iraq began.

Rumsfeld said coalition commanders will soon recommend future troop rotations based on the security situation and political environment in Iraq. In September the Pentagon announced that about 9,400 active-duty soldiers scheduled to finish one-year tours in January will stay at least seven extra days, to avoid a transition to new units during the Iraqi election.

In other comments:

-- Rumsfeld said he believes some Guantanamo detainees have been conducting hunger strikes to capture press attention. Currently, 27 detainees are participating in the hunger strike, including 24 who are being force fed and monitored by medical authorities.

Many of the nearly 500 prisoners at Guantanamo Bay have been held more than 3 1/2 years without charge or access to lawyers. Most were captured in the Afghanistan war, suspected of ties to the al Qaeda terrorist network or the Taliban regime ousted by U.S. forces in late 2001.

-- Rumsfeld said he does not recall talking to Vice President Dick Cheney about undercover CIA officer Valerie Plame whose diplomat husband, Joseph Wilson, publicly questioned the Bush administration's justification for going to war in Iraq. And he said he is not aware of any involvement in the matter by the Defense Department. But he said that with a department of hundreds of thousands of people and a time span of five years, he couldn't be sure.

Cheney's chief of staff, I. Lewis "Scooter" Libby Jr., was indicted Friday on charges of obstruction of justice, perjury and making false statements in the investigation into the leak of Plame's identity.

-- Rumsfeld said that after consulting lawyers and ethics officials, he decided not to sell his stock in a company with an interest in the influenza-fighting pill Tamiflu, which could be used to combat bird flu.

He said he considered every option, but determined it would be a problem to sell the stock, which has greatly increased in value. Rumsfeld has long held the stock and last week repeated his intention to stay out of any decisions on treatments or vaccines for bird flu.

-- He said he had seen no indication North Korea was backing away from plans to continue building nuclear weapons