Ceuta migrant crisis: 28 undocumented migrants found hidden in Spanish flats

Spanish police discovered 28 undocumented migrants hiding in flats in Ceuta, weeks after more than 70,000 people entered the Spanish territory from Morocco.

The flats did not meet adequate hygiene and habitability standards, with some in a building under construction with no water or electricity supply, according to Spanish police.

Three people were arrested and three minors referred to support services.

Ceuta has been embroiled in a humanitarian crisis for several weeks. Most of the people who reached the enclave in late July returned shortly after, but thousands have remained in often deplorable conditions as the small city's resources were overwhelmed.

The situation has created a political storm for Prime Minister Pedro Sanchez. The Spanish leader has attempted to avoid a diplomatic clash with Morocco, while facing criticism from Spain's right-wing parties over security.

Having consistently avoided attributing the crisis to Rabat, with which Spain maintains delicate relations, Sanchez had told CNN on Tuesday that Morocco's "border control failed" during July's rush.

Authorities had detected fresh calls on social media for another rush to Ceuta and Spain's other north African territory of Melilla, coinciding with Morocco's parliamentary election.

But on Wednesday Sanchez told a press conference that "we saw a very large police deployment, at the Ceuta border as well as at the Melilla border" on Tuesday.

"We should acknowledge this too", Sanchez said in New York, hitting back at the right-wing opposition that has accused Morocco of orchestrating the rush and blackmailing Spain.

Sanchez has said Morocco needs to provide "explanations and changes" to avoid a repeat of the influx but that no "solid proof" exists to blame Rabat, which claims sovereignty over Ceuta and Melilla.