Police will fan out in force both in uniform and undercover to keep crowds safe during Las Vegas' extravagant New Year's Eve celebration, authorities said Thursday.

Law enforcement and local government officials held a news conference in front of the Welcome to Las Vegas sign to highlight their plans to protect the public during the holiday. More than 300,000 visitors are expected in town for the festivities.

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Beyond an eight-minute pyrotechnic show featuring fireworks launched off casino rooftops, nightclubs are ringing in 2017 with superstar celebrities and restaurants are pulling out all the stops with elaborate prix fixe menus and champagne toasts.

Measures to keep revelers safe include:

Ban on big bags

A Clark County ordinance that's new this year will ban glass bottles, backpacks, coolers, strollers and large bags on the Las Vegas Strip from 6 p.m. Dec. 31 to 6 a.m. on Jan. 1.

Police say they'll warn people to put the items away in their hotel room or car, and will confiscate the items if their owners are being uncooperative. Violating the ordinance is a misdemeanor, so visitors could face jail time and fines if they don't comply.

Last year, police urged people not to bring such items, but didn't have power to enforce the recommendation because it wasn't an ordinance.

Expect road closures

The Las Vegas Strip will be closed off to vehicles between Mandalay Bay Road in the south and Sahara Avenue in the north from about 6 p.m. on New Year's Eve to a few hours after midnight on New Year's Day. Off-ramps from Interstate 15 near the Strip will also be closed.

Authorities say they're also ramping up efforts to keep cars out of pedestrian areas and prevent vehicle attacks like a deadly one last week at a Christmas market in Berlin. Las Vegas Metropolitan Police Department Sgt. Jeff Clark declined to say his agency's exact plans for physically preventing car incursions, but said barriers will be enhanced compared with last year.

Clark County Commission Chair Steve Sisolak said there will be 4,200 crowd control barriers in place during the festivities.

More hands on deck

It's an all-hands-on-deck situation for Las Vegas police, who are barred from taking vacation during the New Year's Eve holiday period. Clark said all officers will either be working or on call.

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Las Vegas police are getting support from agencies including Henderson and North Las Vegas departments, and they'll also work with personnel from the FBI, National Guard and Secret Service.

Public marijuana use is still illegal

While recreational marijuana use for people 21 and over becomes legal in Nevada on Jan. 1, police reiterated that consumption is not allowed in public places and should be done at home. Using pot in public is a misdemeanor that carries a fine of up to $600.

Driving under the influence of marijuana is also illegal.

Retail dispensaries are not yet allowed to sell marijuana for recreational use and can only provide their products to people with valid medical marijuana cards.