Venezuela's President Hugo Chavez salutes to supporters as he arrives in an open car at Fort Tiuna, to observe a military parade in his honor, on the day of his inauguration, in Caracas. AFP PHOTO

"I will not allow my body or soul to rest in the building of Venezuelan socialism, in the building of a new political and economic system," said Chavez, his hand raised and wearing the red, yellow and blue presidential sash.

"I swear before Christ, the greatest socialist ... that I will achieve the supreme goals of this marvelous constitution, even if it costs me my life," he added. Chavez regularly charges the United States is trying to overthrow or kill him.

The close ally of communist-ruled Cuba paraphrased Argentine-born Cuban revolutionary hero Ernesto Che Guevara, proclaiming "Fatherland, socialism or death!"

In power since 1999, Chavez also made his longer-range plans clear, announcing that he wants to amend Venezuela's constitution to let presidents seek an indefinite number of consecutive terms.

The constitution currently allows two consecutive terms, which would make this Chavez's last - unless the law is changed.

"We are writing the proposed reform on indefinite presidential reelection; if the majority of the people reject it, I will be the first to applaud that," said Chavez.

"The important thing is that the people will make the decision," Chavez added.

However, he said he hoped to wear the presidential sash a third time, making it clear that if allowed, he would run for a third term in 2013.

Chavez earlier had the constitution rewritten to double the number of presidential terms and ease his reforms.

Since taking power in 1999, he has pursued populist and social programmes making literacy and health care top priorities.

With his allies in control of the legislation and courts, he won reelection on December 2.

Chavez has said he would model his socialist system, funded by petrodollars, on the writings of Karl Marx, Vladimir Ilich Lenin and the Bible. Despite its vast oil wealth poverty remains endemic in Venezuela.

"The people voted for the socialist way and socialism is what the people want, what the people need and what the country needs," Chavez said.

Without elaborating, he also called for redrawing Venezuela's political map to give it a "new geometry of power."

Chavez has helped keep communist Cuba's regime afloat with cut-rate oil and other cooperation deals with ailing Fidel Castro, 80, his close friend and mentor whom he sees as a political father-figure.

Monday, Chavez announced he would ask the legislature to approve the "mother of all revolutionary laws" giving him the power to nationalise the energy and telecommunications sectors.

The proposed legislation would also allow him to end foreign control of refineries of heavy crude from the Orinoco belt in the east, he said.

Among those multinationals in the Orinoco belt are US firms ExxonMobil, Chevron and ConocoPhillips; France's Total, Britain's BP and Norways' Statoil.

Chavez said constitutional reform should also be geared toward putting "all hydrocarbons, whether solid, liquid or gaseous," under state control.

As well, he said the country's central bank need not be autonomous.

His remarks rocked the Caracas Stock Exchange, where trading in telecoms operator CANTV and private power generator Electricidad de Caracas was suspended for 48 hours after their shares plummeted at the market opening by 30.1 percent and 20.0 percent, respectively.

CANTV is partly owned by Verizon of the United States, and Electricidad de Caracas is controlled by US power giant AES.

Chavez said "that the Caracas Stock Exchange may fall, but what's not going to fall is the Venezuelan economy, which is stronger than ever."

The swearing in ceremony ended with a military parade during which Chavez, a former army colonel, said he also relied on the military for his upcoming social reforms.

"The people of Venezuela have the soldiers of the revolution and together they will never be defeated; together we will ensure the continuance, the acceleration of this revolutionary process," he said.

In Washington, long at odds with Chavez over political and economic relations, officials deplored the nationalisation plans and called on Venezuela to respect international contracts with foreign investors.

State Department spokesman Sean McCormack said: "The proposals he made concerning nationalisation are a well-worn path that history has shown doesn't usually benefit the population.

"There is an accepted international practice in foreign companies being compensated at fair market value for the assets that have been nationalised and we would expect that Venezuela would follow through on all of its contractual obligations," said McCormack.