Defense Secretary Donald H. Rumsfeld arrived in Peru on Wednesday as part of a short trip to encourage democracy and stability in South America, just one day after Peruvian President Alejandro Toledo swore in a new cabinet following a political shakeup that led to the prime minister's resignation.

Toledo has been struggling to keep his political grip, and his approval rating has fallen to single digits. But U.S. officials praised his efforts to stem the lucrative cocaine trade and to improve the impoverished nation's economy.

U.S. defense officials said they were concerned that instability in the region, including in neighboring Bolivia, could threaten South American democracies and create a climate that would allow drug smugglers and radical leftists to seize power. Rumsfeld's trip is largely aimed at showing support for democracies in the area and minimizing influence by the governments of Venezuela and Cuba.

Rumsfeld is scheduled to meet Thursday with Toledo and his new defense minister, Marciano Rengifo, before returning to the United States. He traveled to Lima after spending a day in Paraguay, where he met with government officials.

On Wednesday morning, Rumsfeld met with Paraguay's defense minister before laying a wreath at the nation's Pantheon of Heroes in the center of Asuncion, the capital. About 50 protesters lined the sidewalk, holding signs in Spanish such as "Bush + Rumsfeld = War" and chanting obscenities at Rumsfeld.

Held back by a line of police in riot gear, demonstrators yelled, "Go home, Americans!" and held up a sign showing photos depicting the Abu Ghraib prison abuses in Iraq, notably the picture of Pfc. Lynndie England holding a detainee on a leash.

The meetings in Paraguay, similar to those expected Thursday in Peru, centered on cooperative military training efforts as well as the battles against terrorism and drug trafficking. Rumsfeld met with President Nicanor Duarte Frutos for 90 minutes Tuesday night.

"Paraguay and the United States of America agree on the necessity to join forces for the consolidation of emerging democracies, the reduction of poverty, the expansion of economic and social opportunity and the strengthening of world peace," said a joint statement issued after the meeting.

Also under discussion was the fact that both Paraguay and Peru have not signed agreements that would grant U.S. troops in those countries immunity from prosecution, thus limiting the amount of assistance and training the U.S. military will provide. The U.S. provides Peru with $112 million in funding for drug interdiction efforts.

Peru fought a brutal counterinsurgency campaign against the Maoist Shining Path guerrilla group from 1980 to 2000. A Peruvian truth commission in 2003 blamed more than half the nearly 70,000 deaths during the conflict on the rebel group.

"Peru has fought and won a war against terrorism," said one senior U.S. defense official. "They are very sensitive to terrorism."