Heavy security restrictions go into effect in Osaka this week for the Group of 20 leaders’ summit, with 32,000 police officers in the streets and officials warning visitors and residents of traffic delays, sealed trash cans and lockers in train stations, and restrictions on movement around major hotels.

The unprecedented measures for the summit, which is expected to draw 30,000 people, have prompted requests from the Osaka Municipal Government for residents to avoid using their cars and to avoid going out for unnecessary reasons during the event due to the expected impact of traffic restrictions.

Nearly 700 Osaka municipal and prefectural schools will be closed on Thursday and Friday, and many school activities on Saturday were canceled due to the security. Many shops and smaller businesses in nine designated security areas (see map) are also likely to voluntarily shut down during the summit period. Some parts of Osaka Castle Park, where the Osaka State Guest House is located and where leaders are likely to gather at some point, will also be closed between June 25 and 29.

Police officers from 46 prefectures will be deployed to Osaka for the June 28-29 event. While most of the summit takes place at Intex Osaka near the waterfront, many leaders, including U.S. President Donald Trump and Chinese President Xi Jinping, are staying at luxury hotels near major train stations in the northern and central parts of the city. The leaders of 37 countries in all and international organizations are scheduled to attend the summit.

Osaka officials warned vehicular traffic in particular is likely to be strongly affected, with extensive roadblocks being set up as VIP limousine motorcades with police escorts move between hotels and the summit location. Areas expected to be most affected include those near JR Osaka and Umeda stations, Osaka Castle, the central Honmachi area, the Namba Station area and Intex Osaka and expressways, especially the Hanshin expressway.

There could be severe delays getting to and from Kansai and Itami airports by bus or taxi. Osaka police and city officials are advising everyone to use trains if they need to use the airport between Thursday and Sunday.

As of late last week, trains and subways in central Osaka and those going to the airports were expected to be running as usual during this time. But municipal officials warned they could be extra crowded due to the road restrictions.

In addition, flight delays at both airports are also possible due to arriving or departing heads of state. Heavy security will also be in place at the immigration and customs areas at Kansai airport.

Public facilities like ward offices will be open, but due to possible congestion the city has asked residents to avoid using them this week.

The 32,000 police deployed to Osaka for the summit is more than the 23,000 who were used for the 2016 Group of Seven Summit in Ise. Osaka and police officials say the heavy security presence is to prevent a terrorist attack.

“One of the advantages of Osaka is that we can convey to the world that it’s a really safe city,” said Osaka police chief Takahisa Ishida said last week at a news conference on G20 security.