SYDNEY, Australia — A few days after the vehicle attacks in Spain that killed 14 people, Prime Minister Malcolm Turnbull of Australia has unveiled a counterterrorism strategy to protect crowded public spaces.

The plan calls for more barriers in busy pedestrian areas to prevent vehicles from entering. The barriers could include posts, steps and even works of art, Mr. Turnbull said on Sunday. Businesses will also be asked to address security risks by working with the police.

“We will never be cowed, nor will we bow to terrorism,” he added. “But what we must do, of course, is take every step we can to protect Australians from the threat of terrorism and terrorist attacks.”

His announcement came just days after two deadly vehicle attacks in Spain. In the first, a van mowed down pedestrians on Las Ramblas, Barcelona’s main promenade, on Thursday. Among those killed was a 7-year-old Australian boy. Hours later there was car attack in the seaside town of Cambrils.