WASHINGTON – Organizers for the Republican National Convention are preparing security for the gathering in Cleveland in July in an unusually combustible environment, in which the threat of terrorist attacks is now joined by the unpredictable behavior of opponents and supporters of GOP presidential front-runner Donald Trump.

After Tuesday’s terrorist bombings in Brussels, officials representing law enforcement, the Republican National Committee and the city of Cleveland say they will be prepared for whatever comes their way when an estimated 50,000 people converge on the Lake Erie city for the July 18-21 convention.

“Our goal is to develop and implement, with numerous participating agencies, a seamless security plan that will create a safe and secure environment for our protectees, other dignitaries, event participants and the general public,” said Kevin Dye, a spokesman for the Secret Service.

Still, some security experts say recent events suggest challenges.

“I would be concerned in Cleveland,” said former Charlotte-Mecklenburg Police Chief Rodney Monroe, who oversaw security during the 2012 Democratic convention in the Queen City. “Cleveland has a lot of elements that would keep me up at night.”

But Monroe, who has spoken with Cleveland convention organizers, said potential nightmares could be alleviated with some well-coordinated planning.

An alphabet soup of agencies – from the Secret Service to the Department of Homeland Security to the military – have been working for months with state and local agencies in developing plans to deal with large numbers of protesters, potential domestic and international terrorist threats, and other concerns.

Despite a sizable lead in delegates won in primary election contests, Trump could fall short of the majority needed to win on the first ballot, forcing a contest inside the convention. He suggested last week that there might be chaos if he doesn’t leave Cleveland’s Quicken Loans Arena, the site of the convention, as the Republican presidential nominee.

“There could very well be riots,” he told CNN’s Wolf Blitzer.

The Republican convention and the Democratic convention in Philadelphia have been designated national special security events, a title given to large-scale gatherings, such as Pope Francis’ U.S. visit last year, that could be targets of terrorism.

Cleveland and Philadelphia are each receiving $50 million in federal grants to help pay for security, an amount that sounds like a lot until you have to start spending it, Monroe said.

“We spent about $48 (million) to $49 million,” Monroe recalled. “Pretty quick, about $25 (million) to $26 million was eaten up by personnel, additional officers. We had to pay for travel, to put them up in hotels, feed them three meals a day.”

Even before the Brussels attacks and the uptick in violence at Trump events, Cleveland officials were scrambling to use the funds to armor up for the convention.

Earlier this month, the city solicited bids to purchase 2,000 sets of riot gear that include hard-knuckled gloves, turtle shell-like upper body, shin and forearm shell protection, and 26-inch retractable batons, according to Cleveland.com. The site also reported that the city is seeking to rent nearly 3 miles of interlocking steel barriers, 3.5 feet high, and to purchase 3,250 feet of interlocking barriers that stand 6.5 feet high.

“We’re expecting people to come and behave, have a great time, leave happy and content,” said Dan Williams, a spokesman for Cleveland Mayor Frank G. Jackson.

The city is ordering 15 police motorcycles, 300 patrol bicycles, 310 sets of riot gear for the bike cops, 25 sets of tactical armor and two horse trailers.

In addition, Cleveland is looking to bolster its more than 1,600-member police department – Ohio’s second-largest – for the convention by recruiting 5,000 officers from surrounding suburbs.