MADRID (AFP) - Around 1,200 migrants tried to storm the border separating Spain's Melilla enclave from Morocco on Thursday (March 3) in the second such attempt in 24 hours, a government official said.

The incident occurred a day after an unprecedented 2,500 migrants made a mass run at the border with almost 500 getting across in what the Spanish government's local delegation said was "the biggest entry attempt on record".

Thursday's incident began around 6am (1pm Singapore time), when Spanish police noticed a huge group of migrants approaching the fence, a delegation spokesman said in a statement.

"At around 7.25 am, after overcoming the Moroccan security forces, they began to jump the fence... throwing stones and using hooks and sticks against the security forces," he said, indicating around 350 managed to cross over.

Initial reports said four members of the Guardia Civil police were hurt in the attempt, he said.

In Wednesday's break-in, which officials said involved sub-Saharan migrants, the delegation said some migrants had bolts screwed into their shoes to help them cross the fence, which "being sharp, carries a huge risk" for the police and security forces.

Melilla and Ceuta, Spain's other tiny North African enclave, are the European Union's only land borders with Africa, making them a magnet for migrants desperate to escape grinding poverty or war.

Claimed by Morocco, the two enclaves have long been a point of dispute in bilateral diplomatic relations, with Madrid insisting both are integral parts of Spain.

In mid-May 2021, Spain was caught off guard when more than 10,000 people swam or used small inflatable boats to enter Ceuta as Moroccan border forces looked the other way.

The influx took place during a diplomatic crisis between Madrid and Rabat over Western Sahara, which has long pushed for independence from Morocco.

Madrid had angered Morocco by allowing the leader of Western Sahara's independence movement into Spain for hospital treatment for a severe case of Covid-19, sparking a tense diplomatic standoff.

The unprecedented border breach was widely seen as a punitive move by Rabat.

Last year 1,092 migrants managed to enter Melilla, a 23 per cent drop from 2020, according to interior ministry figures.