SAN SALVADOR, El Salvador (AP) _ Soldiers fought rebels in two poor neighborhoods of San Salvador on Friday and in scattered encounters north and south of the city, the army reported.

A Salvadoran photographer for Agence France-Presse was killed and a Red Cross worker with him was wounded in Soyapango, one of the neighborhoods where the armed forces said fighting took place overnight.

President Alfredo Cristiani said the national situation remained critical but that his 5-month-old government was not in danger.

A reporter for the French agency said the photographer, Eloy Guevara; the Red Cross worker, carrying a white flag; and a Salvadoran radio reporter were at a gas station at the foot of a hill in an area that saw combat earlier.

Journalists yards away from Guevara when he was shot said he was crossing an intersection with three Red Cross workers when a burst from an assault rifle struck him and ricocheted off a wall.

Two reporters there agreed that judging from the angle of fire, the bullets came from the side of the street where air force paratroopers were in complete control.

Guevara was the second journalist killed since the leftist Farabundo Marti National Liberation Front, or FMLN, began an offensive in the capital three weeks ago.

The other was David Blundy, 44, a veteran war correspondent who worked for The Sunday Correspondent of London.

Gen. Maxwell Thurman, commander of the U.S. Southern Command based in Panama, visited El Salvador on Friday. U.S. Embassy spokesman Jeff Brown said ''the purpose of the visit was to reaffirm U.S. support and his personal commitment to the world of the Salvadoran armed forces.''

The armed forces press office reported fighting overnight in the Ciudad Delgado neighborhood, where leftist rebels remained, and Soyapango. It said the guerrillas had left Soyapango.

Both neighborhoods were major combat zones in the early days of the FMLN offensive, which has made thousands of San Salvador residents homeless.

The offensive radically changed the decade-old guerrilla war against U.S.-backed governments, in which more than 71,000 people have been killed. It brought heavy combat to the capital for the first time and the guerrillas began using anti-aircraft missiles.

Pentagon officials in Washington said introduction of the missiles meant the Salvadoran military, whose air power had faced little challenge, would have to change its tactics.

Military officials said Friday nine soldiers and nine guerrillas had been killed in fighting near Zacatecoluca, 25 miles south of San Salvador, where rebels fired a Soviet-made SAM-7 surface-to-air missile Wednesday for the first time. A military source said the missile missed an A-37 jet fighter.

Salvador's rightist government accused Nicaragua of supplying the missiles and suspended relations. The United States filed a formal protest with the Soviet Union, which arms Nicaragua, and the issue is on the agenda for the weekend summit off Malta between President Bush and Mikhail S. Gorbachev.

One soldier and one guerrilla were reported wounded at Tonacatepeque, 10 miles north of San Salvador.

Cristiani said a state of siege imposed after the start of the offensive would not be lifted until violence subsided. The rules restrict freedoms, including freedom of the press.

San Salvador's mayor asked residents to forgo the custom of setting off fireworks over the Christmas holiday.

Residents of the exclusive Escalon neighborhood began repairing houses that were shot up when guerrillas took over about 40 homes there and in another wealthy district Wednesday. Some residents closed their homes and went abroad or to visit relatives.

American citizens were evacuated from the area during a cease-fire the rebels declared Thursday. More than 200 U.S. Embassy dependents and private citizens left El Salvador on a charter flight.

In Washington, the State Department said two of the damaged homes were occupied by Americans. No residents were reported hurt.

Soldiers from El Salvador's toughest battalions patrolled the streets of Escalon and surrounding neighborhoods.

Streets were littered with spent cartridges, burned-out luxury cars and downed power lines. Guerrillas withdrew under cover of darkness, leaving a few snipers behind.

Soldiers of the Atlacatl Battalion burned a guerrilla's body and dumped it headfirst into a mesh trash basket outside one of the fortified mansions in Escalon.

A crude cardboard sign with a skull and crossbones scrawled on it was jammed in next to the body. It said the Atlacal does not take prisoners.

''There is no man, no law that holds us back,'' the sign said.

A soldier said of the guerrilla: ''He thought he'd scare us. We burned him.''