Media playback is unsupported on your device Media caption Welsh businesses hope for an economic payout from the Nato summit

There is one week to go before world leaders descend on Wales for the 2014 Nato summit at Newport's Celtic Manor.

A security "ring of steel" is already in place at keys sites in Cardiff and in Newport - some 12 miles (20km) of fencing with pedestrian access points.

Police say they must be ready to deal with demonstrations ahead of the event, with the first expected on Saturday.

More than 150 heads of state and ministers including US President Barack Obama will attend the two-day summit.

Their entourage will include around 10,000 support staff, while 2,000 journalists are also expected to attend.

The security fencing, in place for the largest gathering of political leaders Britain will have ever seen, has been going up over the past three weeks.

As well as fencing along roads, paths and cycle routes, pedestrians in Cardiff city centre have to go through access points as Nato "working dinners" will be held in key venues during the summit.

Star Welsh chef Stephen Terry is to serve up a banquet for world leaders in the city on 4 September, promising a menu that will showcase food products from Wales.

Meanwhile, the public is being urged to travel into Cardiff city centre by public transport to avoid delays amid complaints the fencing is causing "absolute chaos".

Restrictions are expected to tighten further on 4 September when the area is "locked down" by security services.

Media playback is unsupported on your device Media caption An estimated £50m is being spent on security measures for the Nato summit in Newport, as Hywel Griffith reports

Security will be provided by 9,500 police officers drawn from all 43 police forces in England and Wales, as well as from Scotland, Northern Ireland, and the Channel Islands.

Ministry of Defence police will also be on duty and seven Nato warships will be moored in or around Cardiff Bay.

The man heading the security operation, which includes 1,500 officers from south Wales, has described it as "completely uncharted territory" for British policing and said "discreet" armed protection would also be used.

Two groups - Stop Nato Cymru and No Nato Newport - are organising a series of protests.

On Saturday a march is to be held in Newport while on Sunday a "Cardiff counter summit" will be held at the city's County Hall.

Image copyright Getty Images Image caption Mounted police patrolling the security fence by Cardiff Castle are among 9,500 officers policing the summit

What is Nato?

Nato is an alliance of 28 countries from Europe and North America, which are bound by the principle of collective defence.

An attack against one member is considered an attack on them all.

The alliance began with 12 countries, including the UK, in 1949 and now boasts former members of the Soviet-run Warsaw Pact including the Czech Republic, Hungary and Poland.

Source: Nato

Image copyright Getty Images Image caption Although the summit is in Newport, some receptions and dinners will be held in Cardiff

Police have been liaising with protest groups over planned protest marches but have warned that anyone trying to enter the Celtic Manor Resort would face arrest.

Sixty leaders from Nato-member and partner nations have been invited to the summit's first day and evening reception.

Prince Charles will host an event for them at the Celtic Manor, with David Cameron, First Minister Carwyn Jones and Welsh Secretary Stephen Crabb among the guests.

To mark the summit, the Royal Mint has struck a limited edition bronze commemorative "coin".

Although not legal tender, the 150 coins feature the Nato logo and the words Nato Summit Wales 2014 in English and Welsh.

Both Cardiff and Newport councils have pledged to keep traffic disruption to a minimum in the lead up to and during the summit.

More than 40 schools across the region are expected to shut early or stay closed as part of the security measures.

Image copyright Getty Images Image caption The cost of the security is being met centrally and not by Welsh police forces