President Alvaro Uribe was sworn in for a second term on Monday with Colombia's capital under virtual military occupation to prevent rebel attacks like those that marred his prior inauguration.
Military helicopters buzzed over Bogota and soldiers in armored vehicles guarded key city avenues as Uribe, Washington's main South American ally, took the oath of office for another four years.
Uribe, 54, said that he was willing to negotiate with rebels but demanded concrete concessions from them first.
"We are not afraid to negotiate peace. What worries me is something different: the risk of not achieving peace and then rolling back security," he said.
"We will never allow a hollow peace," he said after the swearing-in before the president of the Congress.
During Uribe's speech, leftist lawmakers held up photographs of many of the 58 hostages who Revolutionary Armed Forces of Colombia (FARC) rebels proposed exchanging for some of its 500 imprisoned fighters.
One of the photos depicted Ingrid Betancourt, who was captured by FARC four years ago when she was a presidential candidate.
The left accuses Uribe of forgetting about those hostages, who include police, soldiers and some Americans.
Some 30,000 soldiers and police took over the capital on Monday in order to safeguard 11 presidents and several groups of dignitaries at the ceremony.
Security included snipers on rooftops around the presidential palace, and police and army checkpoints along main routes entering and leaving the city.
Authorities looked to prevent a repeat of Uribe's 2002 inauguration, when FARC guerrillas used home-made mortars to lob shells at the ceremony. It was not hit, but one round landed in a nearby neighborhood, killing 21 and injuring 70.
Uribe, a US and British-educated lawyer, promised to crush the 17,000-strong FARC when he was first elected. Although he has not succeeded, he did increase military efforts against the well-armed rebels, and he was re-elected on May 28 with 62 percent support.
Foreign dignitaries at the inauguration included presidents Michelle Bachelet of Chile, Alan Garcia of Peru, Oscar Arias of Costa Rica, Alfredo Palacio of Ecuador, Nicanor Duarte of Paraguay, Leonel Fernandez of the Dominican Republic and Antonio Saca of El Salvador, as well as the vice-presidents of Venezuela and Cuba and Prince Felipe of Spain.
Absent, however, were some of South America's leftist leaders: presidents Hugo Chavez of Venezuela, Tabare Vazquez of Uruguay, Luiz Inacio Lula da Silva of Brazil, Nestor Kirchner of Argentina and Evo Morales of Bolivia.
"That is no coincidence," said Carlos Gaviria, president of the Independent Democratic Pole. "Their absence shows Uribe's discordance with the rest of the continent."
Left-of-center leaders who did attend were Garcia and Arias, both social democrats, and Bachelet, a socialist.
The US was to be represented by Secretary of Commerce Carlos Gutierrez and Secretary of the Treasury Henry Paulson.
Since last week armed attacks and car bombings, that mostly targeted law enforcement authorities, have ravaged several regions of the country.
Authorities said that the attacks were intended to destabilize the country ahead of Uribe's inauguration.
Uribe's government has started peace negotiations with the smaller National Liberation Army leftist rebels, and reached a controversial agreement with right-wing armed groups that led to the demobilization of 30,000 paramilitary fighters, who enjoy favorable terms.