LONDON -- The London Bridge attackers wore fake suicide belts to create "maximum fear" as they carried out their rampage, police said Sunday.

The Metropolitan Police released photographs of the blood-splattered belts, which were made from plastic water bottles wrapped in duct tape.

Attackers Khuram Butt, Rachid Redouane and Youssef Zaghba wore the belts when they mowed down pedestrians on London Bridge then stabbed people in nearby Borough Market on June 3. They killed eight people before being shot dead by police.

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Police Commander Dean Haydon said the attackers may have worn the belts because they planned to take hostages, "or it might be that they saw it as protection from being shot themselves."

Police have also released an image of a pink-colored ceramic knife that was used in the attack.

"It does provide some significant clues," said CBS News security analyst Frank Cilluffo. "These knives aren't mainstays, so clearly you can get a better sense of who's selling them and for what purpose, so it could be useful in the actual investigation itself."

An undated handout photo issued by the Metropolitan Police, London, and made available Saturday, June 10, 2017, of one of the knives used in the London Bridge attack. Metropolitan Police/AP

Geoff Ho, a Sunday Express journalist who was stabbed and injured in the attack, described in the newspaper how he tried to stop the attackers entering a bar packed with people. Ho said "their eyes were full of rage," and he feared they were about to blow themselves up.

"I couldn't just attack," he wrote. "If I charged at them, maybe I could take out one or two. But one of those animals could detonate and kill us all."

Ho was stabbed in the throat by Butt. He credited his martial arts training with being able to fight off the attack enough to avoid being killed.

Police are still appealing for witnesses as they piece together details of the attack. They say the attackers may have planned even worse carnage. Butt tried to rent a 7.5-ton box truck, but his payment was declined and he rented a smaller van instead.

Police found petrol bombs and blowtorches in the van, which crashed on the bridge.

Police are questioning six men over suspected links to the attackers, Pakistani-born British citizen Butt, Moroccan Redouane, and Zaghba, an Italian national of Moroccan descent.