The Catholic faithful in Guam led prayers for peace Sunday in the shadow of North Korean missile threat, with the western Pacific island's archbishop appealing for "prudence" amid an escalating war of words between the US and Pyongyang.

The largely Catholic territory should pray for a "just resolution of differences, and prudence in both speech and action", said Archbishop Michael Byrnes, echoing a flurry of international calls for US President Donald Trump to show greater rhetorical restraint.

A "prayers for peace" lunchtime rally in the capital Hagatna drew around 100 people. But despite Guam having become the centre of a threatened showdown between the United States and nuclear-armed North Korea, many said they were unfazed.

"I am really not scared because if it's our time to die it is our time to die," added Sita Manjaras, 62, a retired teacher from Tamuning.

Father Mike Crisostomo said their response to the threat was to have faith and pray.

"This goes to show to the other worlds, to the other nations and the countries, that Guam maybe small, our faith and our trust is big," he said.

Dora Salazar, 82, who made the 14 kilometre (nine mile) journey from the village of Mangilao for the peace rally, said she was praying for the North's leader Kim Jong-Un.

"We pray that God will touch his heart," she said.

'Fire and fury'

In response to Trump's threat of "fire and fury", North Korea has pledged to have plans ready in a matter of days to launch an "enveloping fire" of missiles towards Guam.

At the island's main church, the Dulce Nombre de Maria Cathedral-Basilica, Father Paul Gofigan told the congregation to be prepared in case North Korea does launch its missiles.

Catholic worshippers attend a "prayers for peace" rally marking the 100th anniversary of Our Lady of Fatima in Hagatna on August 13, 2017. Photo: AFP

"What would you do if you have only 14 minutes left? The thing to do is pray and reflect," he said

"Prioritise your life. This is a wake-up call, no matter what happens".

Trump has been engaged all week in verbal sparring with the North over its weapons and missile programs, declaring Friday that the US military is "locked and loaded."

He has told Guam Governor Eddie Calvo that US military was prepared to "ensure the safety and security of the people of Guam."

While 85 percent of Guam's 162,000 residents are Catholic, with temperatures hovering around 31 degrees Celsius (88 Fahrenheit) many locals and tourists preferred to head to the beach rather than church.

"No one feels threatened. Should we? Definitely not," said Australian tourist Kirstie Bridgement.

"Guam is the most protected island. We feel safer than ever."

The island houses two large US military bases and is home to more than 6,000 US military personnel.

American tourist Bryan Sanchez said it was difficult to understand the threat "especially with the way culture is like with memes, anything is going to be turned into a joke.

"People just aren't, I guess, as aggressive or too worried about that kind of stuff in our day and age."

Meanwhile, two community groups opposed to the presence of the US military in Guam, Independent Guahan and Prutehi Litekyan, have organised a "People for Peace" rally in Hagatna on Monday.

"What's happening in Guam is a global issue, because if our island is attacked, it could be the catalyst for a global catastrophe," Kenneth Gofigan Kuper of the Independent Guahan movement said.

The rally organisers said in a statement that "Guam has been forced in the middle of other nations' conflicts, particularly as an unincorporated territory of the United States.

"As a result, many of Guam's people know the painful and horrific effects of war as World II survivors and as veterans.

"Thus, the members of Independent Guahan and Prutehi Litekyan, both organisations dedicated to the decolonisation and demilitarisation of Guam, feel it is imperative for the community to stand together in a call for peace."