(HAVANA) - Cuba on Monday welcomed the European Union's decision to try to improve ties as "constructive," but still warned the EU had to be respectful of the Communist nation's sovereignty.

Cuba "will look at the invitation drawn up by (the EU) in a way that is respectful, constructive and in-line with its sovereignty and national interests," deputy foreign minister Rogelio Sierra said in a statement.

The EU froze relations with Cuba, the Americas' only one-party Communist regime, in 2003 after authorities there threw 75 government opponents behind bars. It resumed contact, however, upon their release in 2008.

At talks in Brussels, foreign ministers from the 28-nation bloc endorsed a negotiating mandate for a political and cooperation agreement that ultimately will open the way also to broader trade and economic ties.

"I hope Cuba will take up this offer, and that we can work towards a stronger relationship," said EU foreign policy chief Catherine Ashton as ministers greenlighted the opening of bilateral talks on a "Political Dialogue and Cooperation Agreement."

"This is not a policy change from the past," Ashton said. "Just as we want to support reform and modernization in Cuba, we have consistently raised human rights concerns which will remain at the core of the relationship."

Cash-strapped Cuba is certainly keen to attract foreign investment. But it has shown zero inclination to budge on real, meaningful economic or political opening.

Cuba's infrastructure is feeble, and it is economically isolated. It depends on its close ally Venezuela for subsidized oil to keep the lights on in a nation of 11 million.

After five decades of the same regime, Havana still has not engaged in major economic openings. It maintains Soviet-style control over the vast majority of the economy -- though it has allowed more self-employment after firing thousands from government jobs.

Shortages are widespread, with most Cubans spending hours a day trying to figure out how to put food on the table; incomes average $20 a month. Corruption is a major issue and stealing from the government and tourist facilities such as restaurants is rampant.

All media are state-run and free speech and free association are not allowed although they are deemed basic human rights by the United Nations, of which Cuba is a member.

Cuba has refused to consider a multiparty system, insisting it has created democracy.

With the economy in dire straits and the government in charge of most jobs and education, people are left to work with the system somehow -- or vote with their feet.

Sierra, the senior Cuban diplomat, said that in 2008 Cuba and the EU started a dialogue "on reciprocal bases ... and total respect for the idea of non-interference in the internal affairs of states."

"This is still the case today," Sierra stressed, highlighting how steep the EU's uphill battle will be.