Officers were called to the center just before 11 am (10:00 GMT) on Tuesday where they encountered a man “armed with a large knife”, read a police statement.
The suspect has been taken into custody after he was shot by police because he did not obey warnings to put down his weapon.
Two female employees, aged 49 and 24, of the centre, located not far from the Benfica Lisbon football stadium, were killed in the attack, according to a report from TV station RTP.
A police spokesman told the dpa news agency that the deceased had not yet been officially identified and that a “terrorist attack” was suspected, but without ruling out other motives.
Prime Minister Antonio Costa expressed his condolences and solidarity to the families of the victims on Twitter.
It is too early to speculate about the motives for this crime, said Costa. “We have to wait for the results of the investigation,” he said, Aljazeera reported.
Later in the day, Interior Minister Jose Luis Carneiro, said that “everything leads to believe” that the attack was “an isolated act”.
MP/PR