ASUNCION (AP) ― Ousted Paraguayan President Fernando Lugo fought back Sunday against the politicians who engineered his dismissal, setting up an alternative government and pledging to upstage Paraguay’s new leaders at an upcoming regional summit.

Lugo’s new stance marked a dramatic about-face from just two days earlier when it seemed he would go meekly into retirement after the country’s Congress overwhelmingly voted to impeach him.

Since then, Lugo has received a flood of support from South American nations, including the Mercosur trade bloc, which suspended Paraguay from taking part in a summit set to start Monday in Mendoza, Argentina.

Mercosur nations expressed “their most energetic condemnation of the rupture of democratic order” in Paraguay, read a joint statement issued by the Argentine Foreign Ministry.

Meanwhile, Venezuelan President Hugo Chavez said his government will cut off fuel sales to the poor South American country. Venezuela had become a key supplier to Paraguay as Chavez built close ties with Lugo, a moderate leftist.

The developments set back efforts by newly sworn-in President Federico Franco, who over the weekend mounted efforts to justify Lugo’s removal and fend off criticism from regional leaders calling the action an institutional coup.

Earlier Sunday, Franco said newly appointed Foreign Minister Jose Felix Fernandez would represent Paraguay at the Mendoza summit, with heads of state gathering there on Thursday.

“He will take charge of seeking to solve the discrepancies with countries that are our neighbors and friends,” Franco said after attending Sunday Mass. There was no immediate comment from his government after Paraguay’s suspension.

Lugo also said he will attend the summit and even hand over the rotating presidency of another regional bloc, Unasur, to Peru next week, months before it is due to switch in November.

“I will not collaborate with Franco’s government because it is bogus. It has no legitimacy,” Lugo said. Earlier he denounced his ouster as a “parliamentary coup.”

His former Cabinet ministers announced that they were establishing a parallel government to continue Lugo’s policies and would meet on matters of state Monday.

“President Lugo will be with his ministers to take decisions and then inform what those determinations were,” said Augusto Dos Santos, Lugo’s minister of social communication.

Last week Lugo said he would respect the outcome of his impeachment proceedings. After his rapid trial and conviction in the Senate on Friday, he disappeared from sight, and an aide said he was focused on moving his things out of the presidential palace.

But he came out swinging shortly after midnight Sunday, showing up at an emotional demonstration where he told protesters his truncated presidency was targeted because he tried to help the South American nation’s poor majority. Asked whether he had any hope of retaking office, Lugo exhorted his followers to remain peaceful but suggested that national and international clamor could lead Paraguayan lawmakers to reverse his impeachment.

“In politics, anything is possible,” Lugo said.

He also said he agreed to respect the outcome of a process he considered illegitimate at the behest of Roman Catholic bishops in order to avoid bloodshed.

A second “open-microphone” protest took place Sunday and was still going strong well after nightfall with a larger crowd of around 1,000 watching Paraguayans take turns stepping up to speak their mind. At times the protest took on the flavor of a variety show, as passionate orators and folksingers shared the stage with folkloric dancers and moonwalking Michael Jackson impersonators.

All three other full Mercosur members have reacted with alarm to Lugo’s removal, denouncing the fact that the Senate’s impeachment trial lasted just five hours, giving the president little time to mount a defense. Brazil and Argentina announced they were calling their ambassadors home and Uruguay expressed concern.

Chavez also announced that Venezuela was pulling its envoy and would not recognize a Franco government, calling Lugo’s ouster a “coup.”

Chavez’s decision to cut oil shipments could hurt Paraguay, which has received increasing quantities of Venezuelan oil since 2004. Paraguay currently owes Venezuela’s state oil company Petroleos de Venezuela SA nearly $300 million, out of about $400 million in total debts to oil suppliers.

Paraguay’s new government downplayed the Argentine announcement, noting that the last ambassador, Rafael Roma, had already left three months ago after finishing his diplomatic assignment.

Lugo was elected four years ago, ending 61 years of rule by the Colorado Party, on promises of agrarian reform to help the country’s many poor and landless people, but his allies increasingly turned against him in recent years.

Ultimately, a deadly clash this month between police and landless protesters cost Lugo all but a handful of votes in both legislative houses.

Police were attempting to evict about 150 farmers from a remote forest reserve that is part of a large estate. Six police officers, including the brother of Lugo’s chief of security, and 11 farmers died in the clash.

Lugo’s opponents blamed the president. Advocates for the farmers say the landowner, a Colorado Party politician, had used his influence to get the land from the state decades ago, and say it should have been put to use for land reform.

The president also was tried on four other accusations, including that he improperly allowed leftist parties to hold a political meeting in an army base in 2009; that he let about 3,000 squatters illegally invade a large Brazilian-owned soybean farm; that his government failed to capture members of a guerrilla group, and that he signed an international protocol without properly submitting it to Congress for approval.

Franco is set to serve out the rest of Lugo’s term, which ends in August 2013. His government has been recognized by Germany, Canada and Spain.

Franco said Fernandez, the foreign minister, would try to win back the support of Argentina, Brazil and Uruguay.

“There was no break with democracy here. The transition of power through political trial is established in the national constitution,” Franco said.

The U.S. State Department has urged “all Paraguayans to act peacefully, with calm and responsibility, in the spirit of Paraguay’s democratic principles.” It has not said whether the U.S. will recognize the new government.