ASUNCION (Reuters) - Paraguay's Congress moved to impeach leftist President Fernando Lugo on Thursday on charges he mishandled clashes over a land eviction that killed 17 people last week, and the Senate will decide his fate on Friday.
As political allies deserted him, the president refused to resign and vowed to defend himself in a lightning-quick Senate trial that could result in his removal from office.
Paraguay's lower house of Congress agreed in a swift, near-unanimous vote on Thursday to start impeachment proceedings. The Senate later agreed on impeachment rules and will decide on Friday at 4:30 p.m. (2030 GMT) whether to oust the president.
"This president announces that he is not going to present his resignation and that he will fully respect the constitution and the law to face the impeachment trial and its full consequences," Lugo said in a televised address. "There is no valid cause - neither legal nor political - to make me resign."
"This is an 'express' coup because (lawmakers) have done this in the wee hours of the night. They have gotten together, and we believe this is even unconstitutional because it doesn't respect due process," he told television station Telesur late on Thursday.
Lugo, a former Roman Catholic bishop elected four years ago on pledges to champion the needs of the poor in the landlocked, soy-exporting nation, has struggled to carry out his reform agenda due to the opposition's grip on Congress.
If convicted on Friday by the Senate of the charge of failing to fulfill his duties by allowing social conflicts to escalate, Lugo would have to leave office.
Three bishops visited him on Thursday to urge he resign beforehand to keep the peace, but he refused.
"After the decisiveness in the lower house, and bearing in mind that the same parties are represented in the Senate, I see no reason why we shouldn't see strong support for the impeachment," said center-right Senator Marcelo Duarte.
Some critics accuse Lugo of sympathizing with the peasant farmers who ambushed police officers last week when they went to enforce an eviction order on a farm in the rural northeast. The armed clash killed people on both sides.
Legislators also accuse Lugo of having backed a meeting of young Socialists at a site owned by the Armed Forces and of acting meekly to fight a small, violent left-wing group called the Paraguayan People's Army, or EPP by its Spanish initials.
Under Paraguay's constitution, an impeached leader is replaced by the vice president, who completes the presidential term. The next presidential election is in 2013 and Lugo's vice president, Federico Franco - who has been a fierce critic of Lugo - is expected to run for office.
"This was clearly a setup," the secretary general of the presidency, Miguel Lopez Perito, told Reuters. "There are no serious arguments to justify the impeachment of the president and the rupture of a process that is nine months away from national elections."
Lugo, a mild-mannered leftist, has battled and overcome cancer during his presidency and admitted fathering two children when he was still a practicing bishop, which dented his popularity.
On Thursday scuffles broke out when hundreds of pro- and anti-government demonstrators gathered over the impeachment news in the central square of the sleepy capital of Asuncion.
At the same time, small farmers began making their way to the capital to rally behind the president.
"They need to listen to the people too. I don't think this impeachment is the way to go forward. I don't think it's necessary," said teacher Amalia Allende, as she sobbed in the square, carrying the red, white and blue national flag.
Paraguay has been plagued by political instability and is known regionally for its marijuana crops and as a hub for smuggling and money laundering. It is one of the poorest countries in South America.
Regional governments called for stability and democracy to be respected. The UNASUR group of South American nations sent a delegation of eight foreign ministers to Asuncion to meet with Lugo late on Thursday at the presidential residence.
They are scheduled to meet with the president of Congress two hours before Lugo and his lawyers present his defense in the Senate.
"We'll be there to ensure democratic legitimacy isn't breached," Ecuadorean President Rafael Correa said earlier in the day. "Some things are legal but not legitimate."
Officials in neighboring powerhouse Brazil were following events with "close attention (and) concern," a source said.
"The (international) community has understood this situation. The countries of this continent are not going to accept another Honduras," Lopez Perito said, referring to the ousting of a Honduran president in 2009 by the army, which acted on a court order that had backing from Congress.
In a major blow for Lugo, Vice President Franco's Liberal Party withdrew its support for him on Thursday and ordered its four cabinet ministers to quit. That cleared the way for the impeachment push.
Lugo's Liberal allies were angered by his decision to replace the interior minister with a former state prosecutor linked to the rightist Colorado Party after last week's bloodshed.
Six police officers and 11 peasant farmers were killed in armed clashes during last Friday's land eviction in one of the worst such incidents in the country for two decades.
Lugo said on Wednesday that he would establish a committee to investigate the killings, but this pledge failed to ease intense pressure over the police handling of the operation.
"Lugo has plunged the country into chaos with a total absence of leadership to resolve Paraguay's problems," said Fernando Moreno, 35, a Liberal Party supporter demonstrating in front of Congress.
Additional reporting by Hugo Bachega in Rio de Janeiro; Writing by Helen Popper and Hilary Burke; Editing by Anthony Boadle and Lisa Shumaker