BOSTON — Citgo, the Venezuelan government's Texas-based oil subsidiary, has suspended its free heating oil program for the poor in the United States, citing falling oil prices and the world economic crisis.

The joint effort by Venezuelan President Hugo Chavez and Citizens Energy Chairman Joseph Kennedy, the eldest son of late Sen. Robert F. Kennedy, is a controversial program that provides fuel assistance to 400,000 households in 23 states.

Started in 2005 with Kennedy's Citizens Energy, a nonprofit group aimed at reducing home heating cost of low-income and elderly residents, the program sent 100 gallons of free oil a year to eligible households but drew fire from critics who said it was just a ploy by Chavez to undermine the Bush administration.

Citgo donated 100 million gallons last year, according to Citizens Energy.

At a news conference held at Citizens Energy's Boston headquarters, Kennedy said Citgo officials told him of their decision and he was forced to go public so that households expecting the assistance will know what's happening.

"Citgo made it clear that this is not a cancellation of this program," Kennedy said. "But at the end of the day, the tankers are not going to be in front of this building."

Kennedy said "a couple of hundreds of thousands" will be affected by the Citgo suspension, including those living on dozens of Native American tribal lands.

About 20 staffers at Citizens Energy also were told yesterday they had been laid off as a result of the suspension.

Kennedy urged those who have been helped by the program to write to Chavez to share their stories. Kennedy said that Citizens Energy will continue to run some of its heating assistance programs for now, but the majority of its programs outside of Massachusetts will be suspended. "The big kahuna were those Venezuelan oil tankers," Kennedy said.

Kennedy said he was seeking a face to face meeting with Chavez.

Citizens Energy was founded by Kennedy in 1979 in the wake of the energy crisis of the late 1970s with the goal of reducing the cost of home heating oil for the poor and elderly.

Kennedy drew fire from critics of Chavez when he began the fuel assistance program with Citgo. Critics charged that Chavez, a socialist and staunch U.S. critic who famously called President Bush "the devil," was using the heating oil program as propaganda.

"It looks like the cost of bringing Fidel Castro's brand of rich-vs-poor politics to America just got to be too expensive for Venezuela's bellicose president, but it's hardly a surprise that he's pulling out of our economy now that he's crashed his own," said Larry Neal, deputy Republican staff director of the House Energy and Commerce Committee.

Kennedy has responded that critics should hold oil-exporting countries and other trade partners, such as Saudi Arabia, Kuwait, Russia and China, to the same standards.

Yesterday, Kennedy also called out U.S. oil companies for not taking part in his efforts to provide heating assistance to low-income households. "This shouldn't be the responsibility of another country," Kennedy said. "I don't get one barrel from one U.S. company. Not one."