At least 214 irregular immigrants have crossed the Spanish frontier and taken shelter at the Temporary Stay Immigrants Centre (CETI) in Melilla, Spanish newspaper El Pais has reported.
The break-in occurred around 6:30am local time (05:00 GMT) at Ben-Enzar, a crossing point on the Spain-Morocco border.
According to Government documents, one immigrant hid himself in the upper shelter area of the frontier and had to be rescued by the firemen.
The government delegation said that the immigrants threw various objects – including stones, sticks and bottles – against Civil Guard agents at the frontier.
One of the agents was hit by a stick and reported minor injuries.
When the asylum seekers entered the city, they headed for the immigration centre while chanting "victory", the report says.
The asylum seekers asked drivers for directions to reach CETI.
The director of the immigration centre, Carlos Montero, said during an interview with Radio Nacional de España, that he fears the number of immigrants will increase.
Montero then added that the centre, built to house 480 immigrants, is currently hosting 1,300 asylum seekers.
The director committed to guaranteeing more meals and setting up more tents for the immigrants although the immigrants are reportedly likely to be expelled.
Spanish authorities have been criticised after at least 15 immigrants lost their lives when tried to reach the coast of Spanish enclave Ceuta.
Spanish border police fired rubber bullets in an attempt to deter 200 migrants who tried to cross the frontier.
Spain's Ministry of the Interior published a video exonerating border police from blame for the shooting of Moroccan asylum-seekers.
Critics claimed that the video does not show the Civil Guard response to the would-be "invasion" by water, and it does not exonerate the guards.
Despite the death toll, the director of the Civil Guard, Arsenio Fernández de Mesa, described the action of his officers as "impeccable".
In Madrid, the opposition Socialist Party accused de Mesa of lying. Izquierda Plural, a coalition of leftwing and green parties, called for interior minister Jorge Fernández Díaz to step down over the incident.