SAN JUAN, Puerto Rico (AP) _ Saboteurs exploded a bomb in an abandoned house behind the Puerto Rico Telephone Co. at dawn Thursday, showing that pockets of strong resistance remain to the company's privatization even while a huge general strike petered out.

Police patrolling the area, where pickets remain day and night, said they arrested five males _ two just 15 years old _ with four other bombs made of acid, metal, keys and shards of glass.

They identified the adults arrested as Alex Noel Ramos Vazquez, 21, and Luis A. Morales Andaluz, 20, both unemployed, and construction worker Heriberto Olivera Vargas, 21. The three are from the town of Bayamon just south of San Juan.

The arrests came hours after union leaders ended a 48-hour general strike that began Tuesday with a dramatic blockade of the main airport, an aborted bombing and the strafing of a bank. The strike fizzled Wednesday to picket line scuffles with police and an ax attack on a telephone pole.

The general strike was called in support of 6,400 telephone workers who continue their three-week-old strike.

For the first time Thursday, government officials indicated they were ready to talk to the strikers, though not about the sale.

``We can talk about conditions for them to return to work and other matters, but the decision to sell Telefonica _ that's already made,'' Secretary of State Norma Burgos told a news conference.

Gov. Pedro Rossello last week signed a bill completing the $1.9 billion sale to a consortium led by GTE Corp. of Stamford, Conn. and Banco Popular, the island's largest bank.

However, the government committee in charge of the sale said Thursday it was giving serious consideration to a belated offer from the Spanish company Telefonica Internacional S.A., and would make its decision the week of July 20.

The Spaniards took advantage of the dissension to make a higher bid of $2.1 billion, which would more than cover a $25 million penalty imposed if Puerto Rico abandons its agreement with GTE.

The Spanish company reportedly has done a better job of winning over the unions, who fear thousands of job losses.

Puerto Rican officials' recent willingness to talk to the telephone strikers appeared to be a reaction to indications that strikers might be ready to return to work next week if the government promises no reprisals.

Labor leaders were to meet Thursday evening to discuss a change of strategy that could include periodic 24-hour walkouts, said Annie Cruz of the Independent Brotherhood of Telephone Employees.

Economists, meanwhile, estimated the strike has cost the Caribbean island as much as $300 million.

The telephone company said it had lost $10.1 million because of damage caused by saboteurs who slashed telephone cables and left more than a quarter-million islanders without long-distance service this week.