WASHINGTON (CNN) — Secret Service and National Park Service officials are prepping for upgrades to the White House fence after several embarrassing security lapses in recent months.

Authorities are preparing to add 7-inch steel spikes to the top of the fence to deter climbers. The actual installation work won’t begin until this summer, but officials on Thursday were checking the specifications for the spikes.

As a result, the sidewalk along the fence was closed until early Thursday afternoon, the Secret Service said.

The installation is planned for July and will take about four weeks, the Secret Service said. It’s a temporary measure as the agency reviews designs for long-term changes to make the White House fence more difficult to scale.

The security upgrades come after a series of breaches that have cost former Secret Service director Julia Pierson her job in October and led to House investigations into the agency’s operations.

A particularly alarming incident occurred in September, when a 42-year-old Army veteran ran past Secret Service officers and made it into the White House before being tackled.

One month later, a 23-year-old Maryland man was arrested after he, too, climbed the White House fence — though he didn’t reach the building, and was taken down by Secret Service dogs.

And just a month ago, a California man scaled the White House fence but stopped as Secret Service dogs approached him. That man, Jerome R. Hunt, appeared in court Thursday morning for a preliminary hearing.

Twice the White House has seen local residents fly drones on or near its grounds — once when a man accidentally lost control of one he was flying around his apartment and it crash landed at the White House, and once intentionally, when a man was arrested this month after flying a drone in nearby Lafayette Park.

Early in Obama’s presidency, two other major breaches occurred.

One involved party crashers at a 2009 state dinner. Michaele and Tareq Salahi, who’d been on a reality TV show called “Real Housewives of D.C.,” had made it past two Secret Service checkpoints despite not being on the invite list.

In 2011, a man who called Obama “the anti-Christ” fired a semi-automatic rifle at the White House, striking an upstairs window. The bullet was stopped by bulletproof glass, but it wasn’t found until four days later.

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