WASHINGTON (WASHINGTON POST) - Pennsylvania Avenue in front of the White House will close for seven months, beginning on Wednesday (Aug 21), for construction of a new security fence, the National Park Service announced on Tuesday.

The 2m-high fence is being replaced by one about 4m high, with wider and stronger posts, the Park Service said.

The Park Service and Secret Service began work on the new fence around the 7ha White House complex in July.

The work will be completed in eight phases, using more than 1,000m of steel fencing.

The new fence incorporates anti-climb and intrusion detection technology and is designed to mitigate security threats, the Park Service said.

Overall construction is expected to continue into 2021.

There have been numerous incidents in recent years in which people have tried or succeeded in getting over the fence.

In June, a Pennsylvania man jumped the fence, saying "voices in his head told him to."

After his arrest he said he was "on a covert mission" to tell the president about "'Project Armageddon' and that the Mariana (sic) Trench was going to crack in 9-10 years," the Secret Service reported.

The National Park Service said in a news release that the area from West Executive Avenue to East Executive Avenue, in front of the north portico of the White House, will be closed.

Lafayette Square, the north sidewalk of Pennsylvania Avenue and Jackson Place and Madison Place will remain open to pedestrians and cyclists.