ERFURT, Germany (AP) - Pope Benedict XVI is nearing the end of his four-day state visit to his native Germany.

The pontiff celebrated Mass with some 30,000 people in the city of Erfurt. The service went ahead about an hour after a man fired an air gun at a security guard on the edge of the security zone.

A papal spokesman says there was "no worry" about what happened. Police say the alleged shooter was arrested and that there were no injuries.

In his sermon, the pope acknowledged that the collapse of communism in the former East Germany more than 20 years ago has allowed the church to function freely. But he questioned whether that change has brought any increase in faith.

Following the Mass in Erfurt, the pontiff departed for the southwestern city of Freiburg, the final stop on this visit.