The island's Civil Defence Command said Radar Station 490 was being used to monitor vessels around the island, detect boats still at sea and help fishermen move safely into harbour.
As of 9 am on Saturday, the island was experiencing northwesterly winds of force 7-8, with gusts of force 9. A total of 136 vessels carrying 441 people had taken shelter at Bach Long Vi harbour, while authorities said no fishing boats remained within 15 nautical miles of the island and all moored vessels were secure.
Border guards have been issuing storm updates, calling vessels ashore and helping fishermen reinforce moorings. Local authorities have also strengthened homes, protected crops and livestock, and prepared evacuation plans for vulnerable areas.
Haiphong has imposed a ban on tourist boats, fishing vessels and recreational activities at sea since 4 pm on July 3, with all vessels ordered to reach safe shelter by 7 pm the same day.
The city has mobilised more than 15,400 military personnel and 280 vehicles, including armoured vehicles, ships and rescue boats, while police have deployed 830 officers to help maintain public safety and support emergency response efforts.
According to the Haiphong Border Guard Command, authorities had contacted and accounted for 1,626 vessels carrying 4,441 people by 6 am on Saturday. Of those, 1,617 vessels carrying 4,433 people had reached safe shelter, while the remaining two fishing boats, with eight crew members, were expected to dock shortly.
Officials said there were no vessels out of contact or operating in dangerous waters. All 155 floating fish farms, housing 226 workers, and three offshore watch posts had also been secured.
Haiphong authorities said they would maintain round-the-clock monitoring of the storm and coordinate response measures to minimise damage.