(Adds comment and details from Spain)
RABAT/MADRID, March 18 (Reuters) - About 500 people forced their way into Spain's North African enclave of Melilla on Tuesday, Spanish officials said, the largest number to storm the border in almost a decade as increasing naval patrols discourage entry by sea.
Spain has two enclaves in Morocco, Ceuta and Melilla, and migrants from all over Africa regularly try to reach them, mostly by climbing the triple barriers that separate them from Morocco. Deaths and injuries are common.
Making the most of dense fog to sneak up to the crossing and climb the high wire fence, a total of 1,100 people, according to Spanish figures, and about 600, according to Morocco, made a rush across the border throughout the night and morning.
Nearly 300 were arrested and at least 28 were injured, the Moroccan Interior Ministry said.
"There's been a mass rush (which was) unfortunately violent, which has become the norm. On the Moroccan side they threw stones, sticks and other objects at the security forces," Melilla governor Melilla, Abdelmalik El Barkani, told reporters.
Twenty nine migrants were being treated by emergency services in Melilla, according to the Spanish government.
Migrants, throwing sticks and stones, ignored warnings of security forces on the scene and injured five police officers by throwing stones, the Moroccan Interior Ministry said. In a dawn rush, about 120 migrants were arrested, including 28 who were injured and hospitalised in the Moroccan city of Nador, it said.
During the night, at around 0200 GMT, another group of migrants faced with security forces outside the triple fence surrounding Melilla and 150 were arrested, the statement said.
In February, the European Union asked Spain to explain why police fired rubber bullets in warning when a group of African migrants tried to wade and swim to Ceuta. Fifteen men died when the shots caused panic among the immigrants, according to Spain.
Thousands of migrants camp for months around Beni Chiguer, from where the attempts were made on Tuesday. The area is covered in shrubs, providing daytime cover for people who then attempt to cross by night.
Migrants enter the enclaves without official documents, often without belongings and wearing just flimsy shoes and shorts, and are housed in temporary centres until their identity can be determined or until they are moved.
Many end up in continental Spain and either stay there or travel throughout Europe. (Reporting by Aziz El Yaakoubi in Rabat and Emma Pinedo in Madrid; Writing by Paul Day; Editing by Louise Ireland)