US President Donald Trump upped the public row with his own intelligence services in tweets slamming them as "naive" on Iran and in need of schooling.

The broadside was a riposte to a far more sober but equally emphatic rejection by the intelligence community during congressional testimony Tuesday of many of Trump's claims to foreign policy successes.

Insisting that Iran's nuclear program remains dangerous, Trump said his intelligence advisors, who believe Tehran is largely abiding by an international commitment to shelve nuclear weapons ambitions, need to be more realistic.

The Intelligence people seem to be extremely passive and naive when it comes to the dangers of Iran. They are wrong! When I became President Iran was making trouble all over the Middle East, and beyond. Since ending the terrible Iran Nuclear Deal, they are MUCH different, but.... — Donald J. Trump (@realDonaldTrump) January 30, 2019

....a source of potential danger and conflict. They are testing Rockets (last week) and more, and are coming very close to the edge. There economy is now crashing, which is the only thing holding them back. Be careful of Iran. Perhaps Intelligence should go back to school! — Donald J. Trump (@realDonaldTrump) January 30, 2019

"The Intelligence people seem to be extremely passive and naive when it comes to the dangers of Iran. They are wrong!" Trump tweeted. "Perhaps Intelligence should go back to school!"

It was hardly the first time Trump has openly criticised his own intelligence and law enforcement agencies.

However, the extent and vehemence of the criticism and the intensely public way Trump expressed his anger, showed how deep the split is between the White House and some of the country's most respected security officials.

The broadside, including tweets in which Trump touted the success of his policies in Syria and North Korea, followed testimony Tuesday by top intelligence chiefs that was widely seen as contradicting the president's rosy assessments.

In a hearing on global threats at the Senate Intelligence Committee, the top officials took issue with Trump's assertion that the Islamic State militant group has been defeated, and that North Korea can be convinced to forego its nuclear weapons.

They also challenged the president's claim that Tehran is actively seeking nuclear weapons, the justification Trump gave for withdrawing last year from the multilateral treaty on Iran.

They underscored again that they believe Russia meddled deeply on Trump's behalf in the 2016 presidential election,which he has repeatedly denied, and can be expected to do the same in 2020.

The Senate hearing took place weeks after Trump cited a victory over Islamic State to justify his sudden announcement of an immediate pullout from Syria, a move that alarmed the US defense establishment and allies in the Middle East.

And it came just weeks before Trump plans a second summit with North Korean leader Kim Jong Un to negotiate a hoped-for denuclearisation of the deeply isolated state.

0:00 Reports Trump and Putin held meeting without note-taker. 00:00 / 00:00 Share Share on Twitter

Share on Facebook

Clashing assessments

Trump has put great store by his personal relationship with Kim and insisted again Wednesday that there is a "decent chance" of North Korea giving up its nuclear weapons.

But in the intelligence community's annual joint report, the view on North Korea was that its leaders still "view nuclear arms as critical to regime survival."

Trump also doubled down on his claim that the Islamic State group, or ISIS, which used to control large parts of Iraq and Syria, will "soon be destroyed," something "unthinkable two years ago."

In his testimony Tuesday, Director of National Intelligence Dan Coats stated that "ISIS still commands thousands of fighters in Iraq and Syria... and thousands of dispersed supporters around the world, despite significant leadership and territorial losses."

Closer to home, Trump has described illegal immigration by poor Central Americans as a national security crisis that he likens to an invasion and can only be stopped by building border walls.

The issue dominates his domestic agenda and has pushed him into a debilitating row with Congress, which so far has refused to provide wall funding.

Tellingly, the intelligence agencies' group assessment on Tuesday referred to migration and cross-border crime, but did not mention any need for a wall.