It's understood a number of Irish people are on board a coronavirus-hit cruise ship off the US coast.

Twenty-one people have tested positive for COVID-19 on the Grand Princess.

The ship is currently moored off San Francisco and is under strict orders to keep its distance from the shore.

All the passengers and crew are now being tested with plans in place to bring the ship to a non-commercial port.

Donegal man Pat Kelly, the second officer on the ship, is from Moville.

He has contacted family and friends to let them know that he is safe. He was home in Donegal over Christmas and New Year's and returned to the ship in recent weeks.

The Department of Foreign Affairs says the Irish Consulate in San Francisco is in touch with local authorities and is monitoring the situation closely.

The US Vice President Mike Pence has said all 3,500 passengers and crew will now be tested for the virus.

He said 19 crew members are among those diagnosed.

The Grand Princess cruise ship. Image: Princess Cruises

Meanwhile, President Donald Trump has suggested he would prefer to keep the passengers onboard.

"I don't need to have the numbers double because of one ship that wasn't our fault," he said.

He said he would listen to expert advice on the best way to proceed.

Among those on board is 60-year-old Kari Kolstoe. She said passengers were only told about the outbreak after Mr Pence announced it on television.

She suffers from stage four cancer – and is worried about getting home in time for her next round of treatment.

“When we get moved to this facility we will all be tested,” she said.

“Those that test negative may be allowed to leave. Now, I don’t know if we will be able to leave right away.”

The Grand Princess cruise ship. Image: Princess Cruises

It comes after Japanese officials were criticised for quarantining the Diamond Princess Cruise Ship when it experienced an outbreak last month.

Ultimately, around 700 people ended up catching the virus on the ship and six people died.

Experts have claimed the situation was mismanaged and the large number of infections could have been avoided.

The Grand Princess is a sister ship to the Diamond Princess.

Mr Pence said officials are working on a plan to test all those onboard at a non-commercial port this weekend.

Passengers have been told to stay in their cabins, and a military helicopter has been seen lowering testing kits on to the vessel via a 950-foot rope.

The Grand Princess experienced a smaller outbreak on its previous voyage when seven people tested positive.

One of those people later died in California’s first coronavirus facility.