Washington (CNN) New US Secretary of State Rex Tillerson introduced himself to the department Thursday at his first day on the job, urging unity as he acknowledged the lingering strains of the divisive campaign and paid respects to the agency's career men and women.

"I know this was a hotly contested election, and we do not all feel the same way about the outcome," the former ExxonMobil CEO said, "but we cannot let our personal convictions overwhelm our ability to work as one team."

Tillerson started out with a sly joke, apologizing for arriving almost 30 minutes late because he'd been attending a prayer breakfast led by President Donald Trump.

"It seemed at this year's prayer breakfast, people felt the need to pray a little longer," he deadpanned, triggering laughter throughout the jam-packed department lobby where new secretaries traditionally greet the staff on their first day.

In the leadup to Tillerson's confirmation Wednesday, the White House had struck out at State Department employees, over 900 of whom had signed a formal protest about the President's travel ban, arguing that it would make the US less safe. The policy's chaotic rollout meant that State, which oversees visa issuance, wasn't informed about or prepared for its launch.

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