Donald Trump at a press conference at Turnberry Golf course in Turnberry, Scotland, June 24, 2016. REUTERS/Carlo Allegri The lead Donald Trump gained over Hillary Clinton after the terror attack in Orlando was erased in a new poll that puts the presumptive Democratic presidential nominee ahead by 13.3 points.

The Reuters/Ipsos poll released Friday showed that 46.6% of likely American voters supported Clinton while 33.3% supported Trump, the likely Republican nominee.

Another 20.1% said they would support neither candidate. The poll was conducted this week.

Trump closed some of the gap between him and Clinton after the Orlando attack earlier this month, cutting Clinton's lead to 9 points.

Trump's image as a strong leader who will fight terrorism (he renewed his calls for a ban on Muslims entering the US, which he says will help prevent future attacks) apparently resonated with voters after a gunman entered a gay nightclub in Orlando and killed 49 people on June 12. The gunman pledged allegiance to the terror group ISIS during the attack.

But Trump seems to have lost his post-Orlando boost as his campaign has suffered a turbulent week.

He fired his campaign manager, Corey Lewandowski, who had earned a reputation as a hothead with little experience on the national political stage. He was then beset by reports of anemic fundraising numbers that paled in comparison to Clinton's.

In an apparent effort to catch up to his Democratic rival, Trump's campaign ramped up its rapid-response operation, sent out its first fundraising email, and professionalized some of the brash billionaire's tweets.

Meanwhile, Republican leaders, including House of Representatives Speaker Paul Ryan and Wisconsin Governor Scott Walker, continued to express reservations about their new standard-bearer, who has angered some in the party with his fiery rhetoric.

Ryan and Walker both said over the past week that they felt Republicans should follow their "conscience" when deciding to support the party's likely nominee, instead of urging party members to support him.

The Reuters/Ipsos poll only captured some of the voter reaction to Britain's decision in Thursday's referendum to exit the European Union, a move that some pundits say suggests Trump's insurgent candidacy has tapped into a broad and powerful antiglobalization wave sweeping Western countries.

The poll was conducted online and included interviews with 1,201 likely voters in all 50 states. It has a credibility interval, a measure of accuracy, of 3.3 percentage points.