LONDON — It is telling and a significantly deep blow to the Algerian economy that the militant attack and hostage-taking in that country has occurred at a foreign-run natural gas field.

Algeria’s economy, though far from vibrant, is heavily dependent on its oil and gas industry. And the country has been desperately trying to attract foreign investment — something that the hostilities at the joint venture owned by BP, Statoil and the Algerian state company, Sonatrach, is unlikely to help.

“I wouldn’t be surprised if those investors Algeria might be courting are even more wary now than they were before,” said Rachel Ziemba, a Middle East analyst at Roubini Global Economics in London.

The Algerian economy remains among the most state-dominated among the Arab countries, with few private businesses of any size and little foreign investment. Energy extraction accounts for about 60 percent of government budget revenue and 97 percent of Algeria’s exports, according to the C.I.A. World Fact Book. But oil and gas are not big employers, making them of little help in producing jobs in a country of about 38 million people and 10 percent unemployment.