Two Albanian men were arrested after driving their car into a virtually empty Barcelona airport terminal early on Friday yelling "Islamist-type" slogans.
There were no explosives in the car and nobody was hurt with few people there because of a partial lockdown to fight the coronavirus epidemic.
Police tweeted a picture of a grey car inside the terminal with its doors open.
“When they were detained, they made an Islamist-type proclamation and we do not know yet what their intention was,” regional police chief Eduard Sallent told reporters.
In August 2017, militant Islamists used a van to hit pedestrians in central Barcelona and carried out a follow-up attack, killing 16.