Two-Pronged Offensive Isolates Liberia Capital : West Africa: Beleaguered President Doe retreats to his residence for a last stand. Rebel victory is forecast.

Rebels aiming to overthrow President Samuel K. Doe attacked Monrovia in a two-pronged offensive Monday, cutting all major land routes out of the Liberian capital.

The action forced Doe to retreat, apparently for a last stand inside his heavily fortified residence.

People streamed out of the center of the shuttered and barred city as the guerrillas closed in. Heavy automatic gunfire and artillery fire erupted in the eastern and western suburbs.

A Western diplomat predicted that rebel leader Charles Taylor’s National Patriotic Front was close to victory in the rebellion begun six months ago.

“There are no defenses on the outskirts of the city, and once (the rebels) get to the executive mansion, they will find a bit of resistance,” a Western diplomat said. “Then it will all be over.”

Doe was believed holed up in his fortified Israeli-built mansion facing the Atlantic Ocean with 500 troops of his elite presidential guard. Vice President Harry Moniba and three other senior legislators held consultations with officials at the U.S. Embassy.

About 500 other government troops were believed to be in the capital of the West African nation.

Doe, in an apparent last-ditch move, repeated his offer on state-run radio to form a national unity government, which would include the rebel front and all political parties. Taylor already has rejected the proposal.

Rebels were reported within a few hundred yards of the main state radio transmitter, which still was broadcasting music interspersed with repeated broadcasts of the government offer.

The station went off the air intermittently but said it was suffering fuel shortages for a generator being used since Monrovia’s power supply was cut off Friday. Water supplies were cut two days earlier.

All international telephone and telex lines were cut Monday evening, and flights from the Spriggs Payne airfield were canceled because crews could not reach the small, inner-city facility.

Residents reached by telephone said rebels also moved in from the northwest of this city of 500,000 people, cutting the road west to Sierra Leone at the Saint Paul River Bridge.

“It’s terrible, terrible, there are so many (rebels),” one resident said by telephone. “They are armed and coming with vengeance written on their faces.”

Most of Doe’s Cabinet and senior administration officials already have fled, among them Commerce Minister John Wesseh McClain, Doe’s speechwriter and a nephew of President William R. Tolbert, who was assassinated when Doe seized power in a 1980 coup.

Liberian and diplomatic sources said army Chief of Staff Lt. Gen. Henry Dubar resigned over the weekend.

Aviation sources said Defense Minister Boimah Barclay took the last plane out on Sunday to Guinea.

Taylor, a former civil servant who fled the United States to escape embezzlement charges, has said he personally wishes to kill Doe, who has been charged with many civil rights abuses.

In Washington, State Department spokeswoman Margaret Tutwiler said that the United States stands ready to help Doe leave Liberia should he ask for such assistance.

Asked whether the United States is considering evacuating all its citizens in Liberia, Tutwiler said, “The United States is considering all options.” She said 70 U.S. officials and fewer than 800 other citizens remain in Liberia.