Supporters of Chávez devastated by his health setback

Venezuela's political and military leaders gathered at the presidential palace and supporters wept after the government said President Hugo Chávez suffered a serious setback in his battle against cancer.

Some loyal "Chavistas" took to the streets in downtown Caracas, blowing whistles and horns, as rumors swirled that the socialist leader's 14-year rule of the OPEC nation could be nearing an end.

"There is so much sadness and confusion," said one die-hard Chávez supporter, Marisol Aponte, a community worker in the city's slums, her voice choking with emotion. "But we must be strong and put into practice all he has taught us."

In probably its most somber update so far on Chávez's health, the government said that his breathing problems had worsened, he was suffering from a severe new respiratory infection, and his overall condition remained "very delicate."

The 58-year-old president has not been seen in public nor heard from since undergoing surgery in Cuba on Dec. 11, his fourth operation since the disease was detected in his pelvic area in mid-2011.

Addressing the nation from the Miraflores presidential palace, Vice President Nicolas Maduro repeated a charge first made by Chávez himself - that the cancer was an "attack" by his enemies in the United States and by Venezuela's opposition.

A US diplomat had been expelled for plotting against the government, amid an upsurge of conspiracies and sabotage attempts against the Venezuelan government, he said.

"These are the most difficult hours since his operation ... but our supreme responsibility is to keep telling our people the truth," added Maduro, surrounded by grim-faced officials.

Several dozen people gathered from early morning at the Catholic chapel in the military hospital where Chávez has spent the last two weeks since returning from Cuba.

Some prayed aloud, while others wept quietly.

The government has repeatedly said Chávez is fighting for his life. Though short on medical details, officials have said he is breathing through a tracheal tube, unable to speak, and undergoing a new round of chemotherapy.

The government is furious at speculation, particularly among pro-opposition media, that Chávez may already be dead. Opposition leader Henrique Capriles has repeatedly accused Maduro and others of lying about Chávez's condition.

"They never change, that hatred they have shown Chávez all these years. It annoys them that Chávez does not give up, nor the people," Information Minister Ernesto Villegas said.