Relatives of the victims grieve Tuesday as they pay tribute to the victims of a collision between a boat carrying holiday revelers and a ferry off the coast of Hong Kong Island. The boat sank, killing at least 38 people and injuring dozens, authorities said.

HONG KONG — Seven people were arrested in Hong Kong on Tuesday in connection with a collision between two boats that caused at least 38 deaths in one of the worst disasters the city has seen in years.

Those arrested — the two vessels’ captains, as well as five other crew members — are suspected of endangering the safety of others at sea, according to an official statement released late Tuesday. Separately, the government announced that it would form an independent commission to investigate the disaster.

One of the boats sank quickly after the collision just off the coast of Lamma, one of the largest of Hong Kong’s many outlying islands, about 8:30 p.m. Monday, as the city was gearing up for a huge fireworks display that marked China’s National Day. As of late Tuesday, 38 people, several of them children, were confirmed to have been killed. Of the 101 people who were hospitalized, four had serious injuries or remained in critical condition.

The collision involved a scheduled passenger ferry and a vessel belonging to Hong Kong Electric, which operates a power station on Lamma Island and is part of the business empire of a Hong Kong billionaire, Li Ka-shing. That vessel, the Lamma IV, had been carrying more than 120 passengers — staff members and their families — to see the fireworks display in Victoria Harbor — for many, the highlight of a four-day holiday weekend in the city.

The Lamma IV, which according to Hong Kong Electric was built to carry 200 passengers, sank quickly after colliding with the ferry, operated by Hong Kong and Kowloon Ferry, which runs regular service between Lamma and Hong Kong Island. The ferry, the Sea Smooth, was somewhat damaged, but no one on board was seriously hurt.

Witnesses said the Lamma IV sank rapidly, trapping passengers inside.

“Within 10 minutes, the ship had sunk,” Reuters quoted one survivor as saying. “We had to wait at least 20 minutes before we were rescued.”

The collision set off a search-and-rescue operation involving divers, helicopters and numerous police and marine department vessels that picked scores of survivors from the sea Monday night.

Photos taken Monday showed the boat half-submerged, its bow pointing nearly straight up, not far from one of the two ferry piers on Lamma.