Finnish President Sauli Niinistö said on Tuesday that Turkey has agreed to support Finland and Sweden's NATO membership bids, removing a major hurdle to the two countries joining the alliance.

Niinistö said in a statement that a joint memorandum on the matter was signed by Turkey, Finland and Sweden on Tuesday in Madrid ahead of what is shaping up to be a critical summit.

The joint memorandum underscores the commitment of Finland, Sweden and Turkey "to extend their full support against threats to each other's security," Niinistö said.

"The concrete steps of our accession to NATO will be agreed by the NATO allies during the next two days, but that decision is now imminent," he added.

"Poverty and desperation" led to the deaths of at least 50 migrants abandoned in a Texas lorry, Mexico's president has said.

Andres Manuel Lopez Obrador blamed trafficking and "a lack of control" at the border - the worst case of migrant deaths due to smuggling in the US.

Nearly two dozen Mexicans, seven Guatemalans and two Hondurans were among the dead.

Those found alive, including four children, were taken to hospital.

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