Cuba is failing to meet its self-imposed foreign investment targets two years after detente with the United States set off the greatest surge of business interest in the country since its 1959 socialist revolution, officials said on Tuesday in Havana.

Foreign Commerce Minister Rodrigo Malmierca told foreign business people and diplomats at the country's annual trade fair that Cuba has approved 83 foreign investment projects worth more than $1.5 billion since the passage of a new foreign investment in March 2014. That puts the country at about a third of the annual flow required to meet its goal of attracting $2 billion a year in foreign investment.

Even that figure may be optimistic: The list of 83 projects includes many that are in very early stages or have yet to begin construction.

"We aren't advancing, I repeat, at the rhythm that we want," Malmierca said. "We need to keep working hard for deals to become reality without problems, without unnecessary delays."

He said Cuba was working to ease the flow of investments with new measures like allowing foreign businesses to invest in infrastructure projects and in the agricultural cooperatives that produce much of the country's food.

"Our government is willing to resolve the problems that still hinder the completion of these objectives," he said.

Cuba blames most of its economic problems on a U.S. embargo that limits international trade with the island despite new U.S. regulations designed by the Obama administration to ease what Cubans call "the blockade." International business people and increasingly Cuban officials themselves say the island's slow-moving and risk-averse bureaucracy is a major obstacle, with important documents often taking months to move from one official's desk to another.

Investment from European companies appears to be picking up steam, with Cuba in August granting state-backed French firm Aeroports de Paris a concession to renovate and operate Havana's Jose Marti airport.