Political extremist Lyndon H. LaRouche Jr. and six of his associates were charged with conspiracy and fraud on Friday in a federal grand jury indictment that said they borrowed more than $34 million over a four-year period with no intention of repayment.

U.S. Attorney Henry Hudson said the 13-count indictment was the culmination of a two-year investigation which began in October 1986 with an FBI and Internal Revenue Service raid on LaRouche headquarters in Leesburg, Va. A truckload of documents and records was seized on that occasion.LaRouche, who is awaiting a retrial in Boston on somewhat similar charges, was named in all 13 counts. He was charged with conspiracy to commit mail fraud, 11 counts of mail fraud and conspiracy to defraud the IRS.

LaRouche's attorneys unsuccessfully sought Friday to delay the indictment's return until after the Nov. 8 presidential election, saying it would interfere with LaRouche's campaigning in 12 states and the District of Columbia.

But the request for a temporary restraining order was rejected by Judge Stanley Sporkin in Washington.

The grand jury said that LaRouche had not filed a federal income tax return since at least 1979 and conspired to conceal the amount spent on his behalf by having his living expenses paid out of bank accounts in the names of corporations associated with his major organization, the National Caucus of Labor Committees.

Hudson said he expected LaRouche and the other six defendants to appear voluntarily for arraignment in federal court on Monday afternoon.

The grand jury charged that during the 1984 presidential campaign, committees supporting LaRouche for president borrowed $4.3 million.

The grand jurors said that between late 1983 and early 1987, commercial entities controlled by LaRouche borrowed more than $30 million.

The indictment described how the loans were raised by telephone solicitors from individuals across the nation. It described loans from individuals ranging from $165 to $200,000.

Hudson said the telephone solicitors promised specific interest payments on the loans, specific dates for repayment and assured the lenders that the loans were good investments and that the organization had a good history of repayment, all the while knowing that the LaRouche groups had no intention of repaying the money.

The other defendants were William Wertz, described as LaRouche's fundraising chief; Edward Spannaus, described as LaRouche's legal chief; and four individual fundraisers, Michael Billington, Dennis Small, Paul Greenberg and Joyce Rubinstein.

They were all charged with conspiracy to commit mail fraud and various counts of mail fraud.

At a news conference outside the U.S. attorney's office, Dana Scanlon, a LaRouche spokesman, called the indictment "political dirty tricks" inspired by former Justice Department criminal division chief William Weld, who she said had become a legal associate of Paul Brontas, campaign manager for Democratic presidential candidate Michael Dukakis.