TULSA, Okla. (AP) _ The Justice Department says the trial of reputed drug smuggler Jose Abello- Silva has altered the belief the U.S. heartland is ''immune'' from the drug trail between the Colombian jungle and America's inner cities.

''You have a major violator being tried in federal court in their backyard,'' said Justice Department spokeswoman Harri Kramer. ''If they think the Medellin cartel does not have its eyes on the Midwest, they're sadly mistaken and this is demonstrable proof.''

Abello, 35, went on trial more than two weeks ago on charges of conspiring to import drugs and conspiring to possess and distribute drugs.

He was indicted by a federal grand jury in Tulsa on Sept. 2, 1987. The indictment accuses Abello of involvement in a conspiracy to ship more than 1,700 pounds of cocaine and 6,200 pounds of marijuana to the United States.

Abello, who was arrested last year in a Bogota restaurant and extradited in October, has appeared relaxed in the courtroom, smiling at times for a sketch artist and waving when witnesses identified him during testimony. His wife and uncle have sat quietly nearby, his wife rubbing wooden beads in her hands.

Defense attorney Richard Haynes said in opening statements in federal court that Abello ''has never been to Oklahoma, never called to Oklahoma and no one in Oklahoma ever called him.''

But testimony last week from Abello's boyhood friend, Boris Olarte-Morales, sought to explain why the man prosecutors contend is the fourth highest member of the Medellin drug cartel is standing trial in a federal courtroom in Oklahoma.

Olarte said he tried unsuccessfully to arrange a meeting in July 1986 in Aruba with Abello and a pilot, Frank Palmero, so they could combine forces to import cocaine.

About the same time near the rural Oklahoma town of Seminole, authorities arrested a drug courier en route to Colorado. That led to the arrest of two drug dealers, Joe Fagan and Matthew Martinich, who agreed to work for the government.

They called Olarte from Tulsa and arranged to import 500 kilograms of cocaine into the United States. Olarte was arrested in Panama and brought to Tulsa to face charges.

He wanted out and needed money, so he said he suggested to his common-law wife that she resurrect the Aruba meeting between Abello and Palmero.

After a series of alleged meetings in Aruba and Florida, and phone calls and money exchanges between Florida and Tulsa, Abello was indicted in September 1987.

He was arrested two years later in a Bogota restaurant and extradited here in October.

''In Oklahoma, he may be the biggest fish. Elsewhere in the country, he may not be a big fish,'' Ms. Kramer said of Abello. ''Nonetheless, he still is charged with conspiracy to distribute and that is not insignificant. ''