A 24-hour general strike protesting a labour market reform sparked violent incidents in Spain on Thursday, with several people reported injured and more than 30 detained, according to dpa. Pickets tried to block the departure of buses in some places, as well as entrances to some wholesale markets. Some of those involved were arrested. Police also detained a man who attacked a picket with a knife, causing her slight injuries in Torrelavega, in the north of the country. In Madrid, police arrested several people on charges of causing disturbances and destroying public property. In Murcia in the south, a police vehicle was hit by a firebomb, which did not cause injuries. Several people, including five police officers, were injured in "isolated incidents," Interior Ministry representatives said. The strike is against a labour market reform that makes it easier for employers to sack workers, as well as against state spending cuts. The conservative government of Prime Minister Mariano Rajoy believes the labour reform will help reduce Spain's unemployment rate of nearly 23 per cent - the European Union's highest. Trade unions see it as a serious attack on workers' rights. Unions reported a "massive" following of the strike especially in the metal, chemical, textile and food industries, construction and garbage collecting. Railways and buses were due to offer minimum services amounting to about a third of the normal. About 1,240 out of a scheduled 4,500 flights were due to be cancelled, while at least two regional television channels did not broadcast transmissions. The government has pledged that the strike will not persuade it to backtrack on economic reforms which have been encouraged by the European Union.