PORTLAND — Portland Police Chief Michael Sauschuck said police have learned of no threats against Maine’s largest city but the department is heightening its vigilance in the aftermath of Monday’s bombing in Boston.

“We’re giving special attention to critical infrastructure and transportation hubs, and I think that’s a stance that we certainly have locally and what we’ll see nationally, as well, in response to a tragedy such as the Boston bombings,” Sauschuck said Tuesday morning.

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“We know of no threats, credible or otherwise, locally. Obviously we’ll continue to monitor the situation,” he said. “We are in active conversations with our federal partners so we’re up to speed with what’s going on from an investigative standpoint.”