Czech counter-intelligence has issued stark warnings of intensified espionage activity by Russia and China.

Both countries are pursuing a long-term strategy of undermining the West, according to the Security Information Service (BIS).

While Chinese spies and diplomats pose "an extremely high risk" to Czech citizens, Moscow has continued its hybrid warfare strategy to gain influence over this EU and Nato member, it says.

Prague's leafy Bubenec district is home to grand villas, diplomatic missions, the Russian embassy, and an excellent Russian-run cafe.

"Thank you," I said to the waitress, as she laid down a pot of green tea and a slice of lemon tart.

"You're welcome," she replied softly, in Russian-accented Czech.

How many spies are here?
I opened the 25-page 2017 BIS Annual Report, and turned to the section on counter-intelligence activity.

"For Czech citizens, the Russian diplomatic corps remains the most significant source of risk of unwitting contact with an intelligence officer of a foreign power," the report reads.

It highlights an "extensive approach to the use of undeclared intelligence officers using diplomatic cover".

Russia's embassy employs 44 accredited diplomats and 77 support staff while another 18 people, including eight diplomats, are employed at Russia's consulates in Brno and Karlovy Vary.

The exact number of spies using diplomatic cover is known only to Moscow. But privately Czech officials believe it could be as high as 40%. In other words, they think many may be working for Russian intelligence or passing intelligence on to them.

Around the corner from the cafe is a statue of Marshal Konev, the Russian general who liberated Prague in 1945 and went on to crush the Hungarian Uprising in 1956.

A brisk walk takes you through Pushkin Square, then on to Siberia Square and the Russian secondary school. Nearby are the Russian Cultural Centre, the Russian consulate and the Russian embassy - now a major headache for the Czech government.

One diplomatic source, who spoke on condition of anonymity, said the supersized Russian diplomatic presence also posed a threat to neighbouring Germany and Austria.

'What does Russia want from us?'
The disproportionately high number of diplomatic cars registered to the embassy cannot be stopped or examined by police, and can travel easily around Europe's passport-free Schengen travel area.

"Who knows what they've got in the boot?" my source wondered, adding that Prague was now beginning to "push back", denying new Russian requests for vehicle registration.

"What does Russia want from us? It's difficult to answer," said journalist Jaroslav Spurny, who's been writing about intelligence matters for 30 years.

"Partly it's influence. They liberated us in 1945. They 'liberated' us again in 1968. They still see us as their sphere of influence. So on that level it's quite primitive," he explained.

"But we're also part of the EU and Nato. The Russian intelligence services know very well where the weaknesses are, which countries can be exploited."

"The Hungarians - well, the relationship with (Prime Minister) Orban isn't so straightforward. The Poles - relations with them will never be great."

"But with us Czechs it's different. They occupied us for 20 years. They know us. They know how things work."

The BIS report also warns of frenetic Chinese espionage activity, particularly in technology.

A separate alert came this month from the Czech National Cyber and Information Security Agency of a threat from Chinese IT giant Huawei.

"The Chinese approach is de facto just as hybrid as the Russian one," said the intelligence agency, adding that Chinese career diplomats and businessmen represented the same risk as intelligence officers.

China, it says, has three aims:

using Czech entities to undermine EU unity
intelligence activity aimed at important Czech ministries
economic and technological spying

The report has led to a major spat between the BIS and Czech President Milos Zeman, who has made overtures to both Moscow and Beijing a centrepiece of his presidency.

How spy report angered Czech president
President Zeman described the BIS as "dilettantes" and the report as "blather", provoking a rare public rebuke from the agency's director.

That rebuke was countered by presidential spokesman Jiri Ovcacek, who told the BBC: "It is absolutely unacceptable for the director of the secret services of a Western country to indulge in political point-scoring."

Critics accuse the president of deliberately working to undermine his own intelligence services, and insiders claim the BIS is now withholding sensitive information for fear it will be betrayed to the country's adversaries.

A particular problem, they say, are the president's two closest advisers, who lack security clearance to see classified documents.

One formerly headed the Czech subsidiary of Russian oil giant Lukoil and was a key player in Mr Zeman's presidential campaign.

The president's office vigorously denies the claims.

"We certainly don't want people to assume that every Russian is a potential spy," said BIS spokesman Ladislav Sticha.

"What we're saying is this: don't give sensitive information to people you don't know. All we're advocating is common sense."