The US president has confirmed Mr Trump will receive security briefings
US President Barack Obama has confirmed that Donald Trump will get national security briefings ahead of the November election.
However he has warned the Republican candidate, whom he has previously called "unfit" for office, that information from the meetings must be kept secret.
Mr Obama, a Democrat who endorsed his former Secretary of State Hillary Clinton in the 2016 White House race, has made clear his dismay over Mr Trump.
But he says they need to obey the law, and that this is standard procedure.
"We are going to go by the law, which is that...if somebody's the nominee for president they need to get security briefings so that if they were to win, they are not starting from scratch," he told journalists in Arlington.
"They have been told these are classified briefings and if they want to be president they've got to start acting like president."
"That means being able to receive these briefings and not spread them around."
Mr Obama also said the so-called Islamic State continues to be a threat to the US, despite losing significant ground in Iraq and Syria.
The president warned that as the organisation was ousted from more areas in the Middle East, it was shifting its focus to attacks abroad.
He said that lone-wolf believers will still be inspired to launch attacks that are hard to detect and prevent.
Mr Obama said the US has to do a better job disrupting terror networks and intercepting the online messages that can get to troubled individuals and inspire them to act.
He said: "What ISIL has figured out is that if they can convince a handful of people or even one person to carry out an attack on a subway, or at a parade or some other public venue, and kill scores of people as opposed to thousands of people it still creates the kinds of fear and concern that elevates their profile."
"ISIL can't defeat the United States of America or our NATO partners - we can defeat ourselves though if we make bad decisions."
He said terrorism will probably not be eliminated by his administration or that of his successors.
"I haven't gotten numb to it. It bugs me whenever it happens," Mr Obama said.
But he added: "I do think that because of our extraordinary efforts the homeland is significantly safer than it otherwise would be."