Hundreds of youths marched to the din of drums and whistles in central Madrid behind a large black and white banner that read: "We are not leaving, they are throwing us out" while chanting "We don't want to go!".

Smaller protests were held in Barcelona and Zaragoza in Spain and over 30 other cities around the world, from Vancouver to Vienna, where young Spaniards have emigrated in demonstrations organized by a grass-roots group called Youth without a Future.

The group posted photos of the demonstrations on its website, including one of eight youths who gathered in Ho Chi Minh City in Vietnam holding hand-made signs and of a protest of around 50 people staged in Berlin.

"We want to denounce the forced exile which young Spaniards are experiencing due to a lack of job opportunities," a spokesman for the group, Mikel Revuelta, told AFP at the end of the march in Madrid.

The group has gathered over 7,000 brief accounts of young people in Spain who are thinking of leaving the country or of those who have already moved abroad.

The accounts have been published on an interactive global map on its website that can be accessed by clicking on a yellow dot.

They include the story of a doctor who is working as a waiter and tour guide in the Dominican Republic and a designer working as a ski instructor in Iceland.

Spain is struggling through a double-dip recession sparked by the collapse of a decade-long building boom in 2008 that has driven its unemployment rate to 55 percent among those aged 16 to 24 and to a record 26 percent overall.

The jump in unemployment has led tens of thousand of young Spaniards, many of them university graduates, to look for better opportunities abroad in countries such as Germany and Britain and former Spanish colonies in Latin America.

The trend has shows no sign of slowing — fully 70 percent of Spaniards under the age of 30 are thinking of moving abroad according to a study by the Real Instituto Elcano, a think tank, in February.

Last month Prime Minister Mariano Rajoy's conservative government unveiled a €3.5 billion ($4.6 billion) plan to boost hiring of young people and help them start businesses.

The four-year plan includes reductions in social security payments for the self-employed and for companies hiring workers under 30 and training for young people who did not finish high school — like many who were lured by unskilled work on building sites during the building boom.