PITTSBURGH -- A coalition of protest groups plans to march to and gather at a state park during the week of the G-20 economic summit even though they lack permits to do so.

The groups, representing anti-war, environmental and social justice causes, said Tuesday that they'll also fight the city's denial of their permits in court if necessary and petition City Council in hopes of gaining permission.

About 50 demonstrators from the groups gathered at a church Tuesday to decide how to respond to the various permits being denied.

"We are not going to back down," said Pete Snell, a member of the Thomas Merton Center's anti-war committee. The center is a Pittsburgh activist group citing peace and social justice as objectives.

The various groups had wanted to gather at Point State Park during Sept. 20-25, but the city has either denied their permits or said the permits were pending, but subject to withdrawal by the Secret Service.

The park will be used as a command center for police and the Secret Service.

The official summit is Sept. 24-25.

Meanwhile, Pittsburgh officials are telling nearby businesses and residents to prepare, be patient and not to panic.

Just what access will be allowed near the David L. Lawrence Convention Center hasn't been determined, but with security expected to be tight for the world's economic leaders, City Council had decided to close offices and juggle schedules during the summit.

"The magnitude and nature of the G-20 event and its security requirements will make it very difficult to maneuver the streets and public buildings of Downtown Pittsburgh," council President Doug Shields said Tuesday.

And the region's public transportation agency advises that routes will likely change, but that it probably won't know how until shortly before the summit.

Joanna Doven, a spokeswoman for Mayor Luke Ravenstahl, said two perimeters will be set up around the convention center.

One will restrict only those with government-issued credentials to a fenced-in area around the convention center and another around that will restrict vehicle traffic.