The typhoon, which made landfall late Friday, was downgraded to a tropical depression Saturday but continued to dump water on already flooded parts of the country.

A taxi driver was killed when high winds caused a tree to fall on his car in Hanoi, while two others died from electric shock after a cable was felled in northern Son La city, according to an update from the national flood and storm central committee.

In Bac Giang province a 46-year-old woman died after soil from a partially collapsed hill buried her house in the middle of the night, VNExpress news site reported.

Earlier more than 11,000 boats, including several hundred used by tourists at the UNESCO world heritage site Halong Bay, were ordered to stay close to the shore.

The Vietnamese army put 20,000 soldiers backed by helicopters, rescue boats and canoes on standby to handle any incidents.

Kai-Tak swept across the Philippines' main island of Luzon, dumping heavy rain on the Cagayan basin and other areas in the north, killing four people.

The Miami-based National Hurricane Center said Gordon strengthened into the Atlantic season's third hurricane earlier, while Helene made landfall as a weak tropical storm on the eastern Mexican coast.

Gordon was about 590 miles (950 kilometers) west-southwest of the Azores in the central Atlantic Ocean at 2100 GMT, heading east at 21 miles per hour, the NHC said. Its top winds were swirling at 105 miles per hour.

A hurricane warning was in effect for the central and eastern Azores. "Preparations to protect life and property should be rushed to completion," the NHC said.

The hurricane center predicted the storm could continue to strengthen slightly before weakening Sunday over cooler waters as it approaches the archipelago.

The bulletin cautioned Gordon could remain near hurricane strength as it passes near the eastern Azores late Sunday and Monday. The NHC warned that Gordon could cause "dangerous surf and rip current conditions" at the time.

Meanwhile, Helene weakened to a tropical depression as it moved inland just west-northwest of Tampico, in eastern Mexico. But it was still producing heavy rains, with up to eight inches (20 centimeters) forecast in some areas.

Forecasters said Helene was traveling west-northwestward at about five miles per hour, with maximum sustained winds of just 30 miles per hour.

The storm center warned of heavy rains in northeastern Mexico along with strong winds near the coast of northern Veracruz and southern Tamaulipas states before Helene dissipates later Saturday or on Sunday.