Special to The New York Times.

HAVANA, April 9--Violence flared in Havana and other sections of Cuba today as rebels called for a general strike against the Batista Government.  At the end of the first day of clashes the insurgent forces apparently had achieved none of their major objectives in the city,.

At least forty youthful rebels were killed in Havana during the day in gun battles with the armed forces.  There were sounds of firing late in the night.

However, a Government communiqué said only that "many" persons had been killed in various clashes.  Official sources said three soldiers had been wounded in the fighting.

Many of the incidents involving gun battles occurred in Havana and in outlying suburbs.  Attacks on police patrol cars and transportation accounted for the dead.

The Government of President Fulgencio Batista has mobilized ever resource to crush the rebel drive.  The real test of strength here may come tomorrow, when the workers must decide whether to heed the insurgents' summoneses to stay away from their jobs or obey the Government's warnings to continue working.

In a statement this afternoon, the Government said:

"Public order has not been disturbed nor will it be disturbed.  The men in uniform are firm in their posts, in the face of criminals acting under the direction of the Communist party."

The Government also said that all labor centers were operating normally.

The violence in Havana broke out after bands of armed youths entered the CMQ and Progresso radio station at about 10 A.M.  They forced the operators to broadcast records calling on the people to strike.

[A dispatch from Santiago de Cuba, the island's second city, said the general strike began fitfully there at 11:30 A.M.  Except for scattered clashes, Santiago was reported quiet.  Late in the day, telephone communications to New York were cut off.]

Six youths attacked a navy arms store in downtown Havana in an effort to seize arms and ammunition.  All were killed by the police and soldiers.

Another group of insurgents bombed a gas main at the Prado promenade and Animas Street, cutting off the gas supply in that area.  Several hours later, flames were still rising from the main.

An official announcement said the police had pursued "a suspicious automobile" considered to be carrying the perpetrators of the bombing.  At Guanabacoa, near Havana, four of the youths riding in the car were killed in a gun battle.

Electric power was cut off in the old section of Havana and in the Vedado area in the morning.  A Government statement said it was only because of the breakdown of a transformer, but other reports ascribed the cut-off to sabotage.

Despite the assurances of President Batista's Government, Havana was tense.  The inhabitants, long injured to violence, prepared for a siege.  Stores quickly sold out of such articles as candles, kerosene lamps and kerosene, flashlights and canned goods.

Spasmodic firing was heard throughout the city tonight but no information on the incidents could be obtained.

In Old Havana and its suburbs traffic was at a minimum.  Buses leaving town carried a few workers going home but those coming into the city were empty.

Hundreds of patrol cars filled with soldiers and policemen armed with machine guns and rifles circulated through the city.

At the Presidential Palace, in Old Havana, big searchlights were installed on the roof.  These swept the adjacent streets at intervals.  Policemen armed with rifles were on duty in all streets near the palace.  The reinforced palace guard was alerted.

A number of buses and huge trucks carrying merchandise into Havana were burned tonight on the central highways between Colon in Matanzas Province and Havana, according to travelers arriving here.

The fight between rebel forces and Government troops has intensified in Oriente Province, a Government source said.

The Government sent six medium-size Patton tanks to Oriente Province today.  These tanks were purchased from the United States Government recently.

At Boniato, about twelve miles from Santiago de Cuba, the capital of Oriente Province, two rebels and four soldiers were killed in an encounter.  The rebels seized a fleet of trucks and cut down huge trees to block the highway.

HAVANA, April 9 (AP)--The fighting centered in the port district of Old Havana.  But one bomb exploded only two blocks from the heavily guarded Presidential Palace.

Workers at some factories and in the telephone, electric and gas companies left their jobs.  Communications and electric power were out in sections of the city for a time.  But the strikes were only temporary.

Probably not more than 100 rebels were involved in the initial shooting.  Rebel leaders known to many Cubans returned to their hiding places.  They told friends they felt sick that supposedly well-laid plans for a block-to-block uprising had gone astray.