More than 900 ‘no-go’ places with large numbers of illegal migrants are concentrated in EU capitals, such as Paris, Stockholm, Berlin and London, the Hungarian government says, adding no one knows how many terrorists arrive undetected.

“The "no-go" areas can’t or almost can’t be controlled by the authorities. In European cities such as Paris, London, Stockholm or Berlin, where there is a high number of immigrants, more than 900 of these "no-go" zones exist,”says the website, launched this week by the government ahead of a referendum in Hungary on the EU quota plan.

READ MORE: Hungary to hold referendum on EU migrant quota plan

“The mandatory European quotas increase the terrorist risk in Europe and imperil our culture,” the website says.

“Illegal migrants cross the borders unchecked, so we do not know who they are and what their intentions are. We do not know how many of them are disguised and may be terrorists.”

The website also showed a ticking clock representing an asylum seeker arriving in the EU every 12 seconds.

Those who come to the EU illegally “do not respect our laws and do not want to share common cultural values,” the website says.

“If we do not act, we will not recognize Europe in a few decades.”

Hungarian PM urges building of fence on Bulgarian, Macedonian borders with Greece https://t.co/rhM0riKXwZpic.twitter.com/DLlAZ4AGIZ — RT (@RT_com) January 23, 2016

The Hungarian government has long rejected a mandatory quota for the resettlement of migrants and refugees. To tackle the crisis, it argues the EU should secure its external borders.

In September 2015, in an attempt to prevent migrants from illegally crossing into Hungary, the government decided to erect a fence on the border with Serbia. It also introduced tough punishments of up to three years in prison for those abusing the border crossing or damaging the barrier.

However, the four-meter-high, razor-wire fence hasn’t stopped thousands of illegal migrants from forcing their way into the country.

In 2015, over one million asylum seekers arrived in Europe, according to data from the International Organization for Migration. Most came from Syria, where a civil war has claimed the lives of 250,000 people and displaced 12 million others since 2011, UN figures show. The asylum seekers also come from Afghanistan, Iraq, Libya, Eritrea, Mali and other countries.