The Spanish government has apologised to the people of Ceuta for the migrant crisis that has affected the city for weeks and it has unveiled plans to overhaul the country’s immigration laws.

“I want to apologise to all those who may have felt, or who even still feel, abandoned or not sufficiently cared for,” Defence Minister Margarita Robles told a parliamentary committee.

“I have witnessed first-hand your feelings of anxiety, of abandonment, of lack of safety.”

At least 72,000 migrants crossed from Morocco into Ceuta, a Spanish exclave in North Africa on 30 and 31 July.

Most of the migrants swam around the border fence and at least 100 people died during the mass crossing, according to figures from Ceuta’s mayor, Juan Jesús Vivas.

The vast majority of the migrants returned to Morocco within hours of their arrival, but several thousand remain in Ceuta, many of them children, and most sleeping rough on beaches or streets.

The Socialist government of Prime Minister Pedro Sánchez has been under mounting pressure to resolve the situation, with many residents and the local authorities in Ceuta, which has a population of 84,000, complaining that it is unsustainable.

The Sánchez government has now declared a situation of interest for national security in the city, centralising management of the crisis. Territorial Policy Minister Ángel Víctor Torres has been tasked with co-ordinating the response, relieving the Ceuta local government of that responsibility.

Coinciding with the government’s moves and Robles’s parliamentary appearance – the first by ministers on this issue over the coming days – changes were also announced to migration and asylum legislation.

Interior Minister Fernando Grande-Marlaska said the reforms would seek to ensure Spain that was fully in line with new EU regulations and that its process was “orderly, efficient, and… [provided] all possible guarantees”.

It will include limiting to three days the amount of time an undocumented migrant can spend undergoing medical, biometric and legal evaluation on arrival – EU regulations allow this period to last up to seven days.

The reforms will also create a two-speed system for processing asylum requests, in theory accelerating cases deemed urgent.

However, the information provided by government ministers has left some questions unanswered.

Robles told parliament that agents of the CNI intelligence service had shared information about a possible imminent migrant crossing with security forces shortly before it happened, but Grande-Marlaska appeared to contradict her.

“There was no report that hinted that on 30 July what eventually happened was going to happen,” he said. Robles later said that the information had not been conveyed via a report.

Sánchez has blamed traffickers and social media activity for the mass crossing.

However, many others have pointed the finger at Morocco, which in the past has been accused of using the borders with Ceuta and its sister city Melilla to pressure Madrid or the EU on political issues.

“The crisis in Ceuta didn’t begin on 30 July,” said Esther Muñoz of the conservative People’s Party (PP), as she questioned Robles in parliament.

“It’s been brewing for years and you know it, because you know that [the Moroccan authorities] have spent years sizing us up, sizing up our ability to respond and our willingness to do so.”

The crisis has raised concerns in Spain about Moroccan claims to Ceuta and Melilla.

Last week, Moroccan Justice Minister Abdellatif Ouahbi spoke of his country’s “historical and geographical right” to the cities and proposed talks with Spain on the issue.

Robles told the parliamentary committee she not would not allow “any minister from any government, in this case Morocco, to question the Spanish status of Ceuta and Melilla”.