Washington, DC (CNN Business) Hackers looking to breach US computer networks sharply intensified their efforts following the death of Iranian military leader Qasem Soleimani, but have had limited success, according to internet security researchers and state government officials.

Soon after the strike that killed Soleimani, Iran-based attempts to hack federal, state and local government websites jumped 50% — and then continued to accelerate, said network security company Cloudflare.

Over the course of 48 hours, attacks traced to Iranian IP addresses nearly tripled against targets around the world, Cloudflare said, peaking at half a billion attempts per day.

Cloudflare CEO Matthew Prince called the increase "statistically significant" in an interview with CNN. He added that the true number of attempts was likely higher, given that the company has a limited view of the wider internet.

"That would be very atypical to happen on its own," Prince said of the spike. "That, I think, you can safely correlate directly to the death of the Iranian general."

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