CARACAS -- Venezuelan Vice-President Nicolas Maduro took the place of ailing President Hugo Chavez on Tuesday by delivering a short speech and turning in a state-of-the-nation report amid legal debate about his legitimacy.

Maduro submitted the report in writing from Chavez's government while the president remained in a Cuban hospital undergoing treatment after his fourth cancer-related surgery. Opposition politicians argued that the annual speech should have been postponed because the president is supposed to deliver it, and some walked out in protest.

Maduro announced during the speech, a day after visiting with Chavez in Cuba, that the president had designated former vice-president Elias Jaua as the new foreign minister. Maduro had kept the foreign minister's post after his appointment as vice-president in October.

Opposition leader Henrique Capriles said the naming of Jaua as foreign minister should be reviewed because it was unclear under what authority the vice-president was acting when such powers belong to the president alone.

Only a portion of the opposition lawmakers walked out of the session. "We have an illegitimate government," said lawmaker Maria Corina Machado, one of about a dozen who left.

Oil Minister Rafael Ramirez rejected the opposition's allegations that the government was acting illegally by going ahead with the special legislative session.

"There's no constitutional controversy," Ramirez told reporters, calling the politicians who walked out "the most extremist sector of the far right."

Re-elected in October, Chavez has not made any public comments since his latest cancer surgery Dec. 11.

He has been fighting an unspecified type of pelvic cancer, and his long silence has fed speculation about why he hasn't addressed the country by phone on television, as he did during past treatments in Cuba. Government officials have said Chavez is being treated for "respiratory deficiency."

Officials have indefinitely postponed Chavez's inauguration despite complaints by the opposition that the move was unconstitutional.

During last January's the state of the union address, Chavez spoke for nine hours before lawmakers even as he was undergoing cancer treatments.

This year, Maduro spoke for about 15 minutes and turned over to National Assembly President Diosdado Cabello two red books containing the government's annual report.

Maduro cited a clause in the constitution that says the vice-president may present reports to the legislature if asked to do so by the president.

"Nicolas didn't come to take the place of the president. He came to bring the documents ... under instructions from the president," Cabello told reporters.

Earlier Tuesday, Maduro said Chavez has been making progress in his treatment for a severe respiratory infection and asked questions of his aides during a visit Monday.

Maduro said he and other officials provided Chavez with an update on "the government in a new stage" and other matters.

"He asked our friend Rafael Ramirez about (certain) aspects" of the government, Maduro said in a televised meeting with state governors.

"Our commander is climbing the hill, he's advancing, and that fills us with great happiness," he said.

Maduro expressed gratitude to Chavez's medical team but didn't give details, saying only that Chavez "is in battle."

Before the legislative session, a crowd of government supporters gathered outside the legislative palace in Caracas, wearing the Chavista movement's signature red.

Francisca Harvey, 46, a member of the pro-government group Frente Francisco de Miranda, eagerly awaited Maduro's speech as loudspeakers blared the song "Chavez, heart of the people."

"He's a strong man," Harvey said. "It's important that we have him healthy."

Another woman outside the palace gates, Emiliana Quintero, a 54-year-old beautician, said she was loyal to the new government, even without Chavez present.

"We are going to support Nicolas while the president recovers," Quintero said, referring to the vice-president.

Dozens of Chavez supporters were allowed through the gates into the courtyard of the National Assembly, and they chanted: "With Chavez and Maduro, the nation is secure."

As the opposition lawmaker Machado entered, some in the crowd began chanting: "They will not return!"

Maduro made his comments about Chavez's health at a gathering of state governors in Caracas after returning from Cuba along with Ramirez, Cabello and Attorney General Cilia Flores.

Three opposition governors attended the meeting, including Capriles, who was defeated by Chavez in the presidential election in October. Capriles shook hands with Maduro in a brief exchange at the event.

During Chavez's five-week absence, some Venezuelans have begun speculating about whether his cancer could force him from office and require a new presidential election.

While many of Chavez's followers said they hope he will recover and return home, opposition lawmaker Carlos Ramos said Maduro's repeated appearances in the president's place suggest an effort to promote him as a candidate.

"What I hope is that they call elections soon," Ramos said.