Continued from page 1

A group called the Masked Brigade claimed responsibility for the attack, saying it came in retaliation for Algeria’s support of a recent French military operation against Islamist extremists in northern Mali, and promised further such attacks. The group said the operation was two months in the planning.

Mr. Yousfi maintained that “Algeria had the means to secure our installations” and expressed doubt that any foreign companies would leave the oil-rich nation that is the third-largest supplier of natural gas to Europe.

Geoff Porter of North Africa Risk Consulting said the attack had sent shock waves through the foreign oil and gas companies operating in Algeria and put them into a crisis mode.

“For the immediate term, this means that the Algerian hydrocarbons sector will enter a holding pattern for the next month or so, possibly resuming meaningful activity at the beginning of March,” he said.

But he agreed with the minister that “it is extremely unlikely that Algeria will witness a mass exodus of foreign oil companies.”

• Paul Schemm reported from Rabat, Morocco. Associated Press writer Rukmini Callimachi in Segou, Mali, contributed to this article.