Donald Trump has made an unsupported assertion that terrorist acts in Europe are going unreported.

The US president said: "All over Europe it's happening. It's gotten to a point where it's not even being reported.

"And in many cases the very, very dishonest press doesn't want to report it. They have their reasons, and you understand that."

In fact, Mr Trump and his team have cited only one example of a deadly terrorist attack anywhere going unreported, the one that did not happen in Bowling Green, Kentucky.

Adviser Kellyanne Conway spoke about a Bowling Green "massacre" that did not take place, correcting herself when she was challenged on the error.

As for Mr Trump's claim about Europe, it is probably true that you have not heard of every attack on the continent that can be tied to terrorism.

Scores, if not hundreds, happen every year and many do not rise to the level of an international audience because they cause no casualties or little or no property damage, or are carried out by unknown assailants for unclear reasons.

One exhaustive list is the Global Terrorism Database, maintained by the University of Maryland, listing 321 episodes of suspected or known terrorism in western Europe alone in 2015.

Many are anti-Muslim attacks against mosques, not the brand of terrorism Mr Trump has expressed concern about.

And many are attacks undertaken for right or left-wing causes that have nothing to do with Islamic extremism or xenophobic attacks on mosques.

Examples from 2015 that were largely under the radar of Americans include: :: On October 24, assailants set fire to the home of a Socialist Justice Party member in Gothenburg, Sweden, one of series of attacks against the party that day.

:: In the UK, assailants set fire to the Whitton Methodist Church hall in Richmond on September 13, with no reported casualties and no one immediately claiming responsibility.

:: On January 17, gunmen opened fire at a bar in Londonderry, Northern Ireland, causing no casualties. Dissident Republicans were thought to have been behind the attack.

The database defines a terrorist act as one aimed at attaining political, religious, social or economic goals through coercion or intimidation of the public, outside acts of war.

The devastating attacks by Islamic extremists that year are also on the list, among them the murderous assault on the Paris offices of the satirical magazine Charlie Hebdo and the even bloodier attack at Paris' Bataclan concert hall, the worst in a series of killings in one day.

Those attacks and other deadly ones in Europe received saturation coverage for days.

But even the smaller, non-lethal acts of terrorism received coverage: The database itself is built from media reports.

Mr Trump made his latest claim before a broad audience on live television, while speaking at Central Command headquarters in Florida.

On Air Force One, before a smaller audience, Trump spokesman Sean Spicer said the president did not really mean that terrorist attacks received no coverage.

Mr Trump's actual complaint, he said, was that such acts do not get enough attention.

"He felt that members of media don't always cover some of those events to the extent that other events might get covered," Mr Spicer said.

"Like a protest gets blown out of the water, and yet an attack or a foiled attack doesn't necessarily get the same coverage."

The White House later released a list of 78 worldwide attacks it described as "executed or inspired by" the Islamic state terror group.

Most on the list did not get sufficient media attention, the White House said, without specifying which ones it considered under-reported.

Attacks on the list that had high death tolls were given blanket coverage, such as the Brussels bombings in March, the San Bernadino, California, shootings in December 2015, and the Paris attacks in November 2015.

Some with a smaller death toll, such as two attacks in Canada that killed one soldier each, were also covered at the time and well known.

The White House did not point to any examples supporting Mr Trump's contention that terrorist attacks were "not even being reported".

Less than half of the 78 incidents the White House listed occurred in Europe.