Poland has introduced random border controls to ensure security at this month's NATO summit in Warsaw and Pope Francis' meeting with world youths in the south.

Interior Minister Mariusz Blaszczak said the checks introduced Monday will carry on through Aug. 2. He said travelers from within the visa-free Schengen zone should bring their passports or other ID documents and others should carry their Polish visas.

The checks will be done at airports, sea ports and on borders with other European Union states, including Germany, the Czech Republic and Slovakia. An agreement allowing residents of Ukraine and Russia's Kaliningrad exclave to travel 50 kilometers (31 miles) into Poland has also been suspended.

Poland routinely introduces border controls during big events, but security has been heightened further following terror attacks in Europe.