By Irina Ivanova and Tsvetelia Tsolova

SOFIA (Reuters) - More than 160 people were arrested in Bulgaria during a second successive night of protests against the Balkan country's large Roma minority, the nation's worst violence for 14 years, and police prepared for more trouble on Wednesday evening.

The unrest, provoked by the death of a young man which some have linked to a Roma clan leader, has drawn attention to the tensions in the European Union's poorest country as it struggles to emerge from deep recession.

Hundreds of youths, frustrated by a lack of jobs and what many describe as a climate of impunity for organized criminals, have taken to the streets in 14 towns.

"Gypsy terror: How long will it take, how long we will be quiet!" read a banner at one of the demonstrations in the capital Sofia and other cities. Police said about 2,200 people took part in the Sofia protest.

"We have more obligations -- we pay our taxes, we behave normally -- while they (Roma) have more rights," Maria Borisova, who attended the protests in Sofia, told bTV channel.

The unrest is Bulgaria's worst since 1997, when an economic crisis and hyperinflation brought Bulgarians onto the streets, though there has been some violence against the Muslim minority this year.

Bulgaria, which holds a presidential election next month, has failed to reap some of the rewards of EU membership, having been barred from the passport-free Schengen zone because of high levels of corruption.

"There is a risk of escalation (of tension) -- we are in a pre-election period," Deputy Interior Minister Veselin Vuchkov was quoted as saying by state news agency BTA, adding that police had stepped up security.

About 400 people have been arrested since the weekend, when residents of Katunitsa, 160 km (100 miles) east of Sofia, blamed Roma leader Kiril Rashkov for the death of a 19-year-old man and set alight several of his houses and cars.

Many of them have been released and some were fined for public order offences.

Police said on Wednesday that Rashkov, 69, known as Czar Kiro, had been arrested and charged with making a murder threat.

The chief prosecutor has called for the rapid arrest of people who incite racial and ethnic tension. Roma make up five percent of the 7.4 million population, and Muslims, many of them ethnic Turks and some also Roma, account for 10 percent.

Police are prepared for more unrest, a spokeswoman said but declined to give details.

"PURELY RACIST"

Roma are a significant minority across central Europe and a lack of integration in countries like Romania, Bulgaria, Hungary, the Czech Republic and Slovakia prompts regular flashpoints and feeds support for far-right political parties.

In Bulgaria, the right-wing Attack party has only about 4 percent support but is a key partner of the ruling GERB party.

Many Roma try to move west, but this led to a wave of deportations from western Europe, especially France, last year.

Protesters have chanted anti-Muslim and anti-Roma slogans and gathered near Sofia's mosque, but government officials say the unrest was not ethnically motivated.

"This was a purely criminal act and not an act of ethnic tension," Rosen Plevneliev, presidential candidate for GERB and a close ally of Prime Minister Boiko Borisov, told Reuters.

The Ombudsman, Konstantin Penchev, said the protests had taken a more sinister turn since the weekend.

"People in Katunitsa took to the streets for a just reason, against an oligarch living above the law," Penchev said. "In the streets of the big cities, people went out with quite different slogans -- not against the oligarchy but purely racist."

Many Bulgarian Roma, who live in big city ghettos, often in homes without running water, fear attacks and have stopped their children going to school for a third day.

In the southern city of Dimitrovgad, Roma armed with axes and knives stayed up all night guarding their homes, and families slept outside fearing attacks on their buildings.

"Roma integration is an old topic. Many governments have done almost nothing about it over the last 20 years and more, now it must be made a priority," said Plevneliev, favorite to win the largely ceremonial presidency in the October 23 vote.

(Writing by Sam Cage; Editing by Tim Pearce)