Foreign investments spark security fears among Nordic leaders

"If you don't have a security cooperation with a country, you can not make sure that the people working [in sensitive industries] are secure enough for the type of work they perform," Solberg warned at a press conference.

"Modern technological and globalised societies have many advantages, but they also give rise to new security challenges that need to be dealt with".

Sweden's prime minister Stefan Lofven said it was "an issue that concerns us all".

"We can see also a pattern of increased activity in our Nordic region".

"From a Swedish perspective it is clear we must monitor and control these activities better. We are discussing a new framework for screening foreign direct investment at the Nordic, as well as the EU, level," Lofven said.

The problem of foreign investments has also hit Iceland, said prime minister Katrin Jakobsdottir.

"The single biggest issue in Iceland is related to investment in land," she said - but also mentioned foreign investment in new technologies and telecommunication as worrying.

As members of the European Economic Area (EEA), any new EU legislation would also concern Norway and Iceland, she pointed out.

Finland's prime minister, Juha Sipila, said his country had seen a record high in foreign investments and acquisitions last year, particular in knowledge-intensive business services.

"Within the EU it is sometimes a problem to track real owners of investments," he warned.

Finland introduced stricter control on investments in the defence sector and in companies critical to society in 2012, and is currently tightening the rules further.

"In the EU it is important to monitor the investments in strategic sectors. The EU has one of the worlds most open investment regimes - as acknowledged by the OECD," he said, adding that it should remain open.

"We need to make sure that the EU remains the number one destination for direct foreign investment, which is in general a major source of innovation and growth and jobs."

Denmark's prime minister Lars Lokke Rasmussen also acknowledged foreign investment's importance.

"They are crucial to our welfare, so basically we welcome foreign investments. But we can not afford to be naive. In a few cases foreign investment can pose risk to national security [or] public order, for example: investments in critical infrastructure, especially if foreign states are involved," he said.

He underlined commitment to ongoing work in the European Commission on a framework for screening foreign investments in the EU.

The Nordic leaders agreed in Oslo to seek a joint position with the EU on the issue.

Iranian plot

More pressingly, the Nordic countries were forced to work quickly together, as the Danish intelligence services on Tuesday confirmed that Iranian agents had attempted to carry out a plot to assassinate an Iranian-Arab opposition figure on Danish soil.

"It is totally, totally unacceptable," said Danish PM Rasmussen in Oslo.

In close cooperation with Norwegian and Swedish security services, an Iranian man with refugee status in Norway has been arrested in Sweden.

The Norweigian-Iranian man was arrested in Gothenburg, Sweden. The suspect has maintained his innocence but will be held in isolation until 8 November.

According to the Danish prime minister, it is not only a Danish problem.

"This is not a narrow Danish phenomenon. I know for certain that the Iranians have also performed activities in other European countries. Therefore, a strong European signal is needed", said Rasmussen.

"We are very concerned with the situation that has arisen in Denmark and, in particular, that a Norwegian-Iranian is involved. There is also a police investigation in Norway, said Solberg.

Solberg said she would be awaiting further information from her police before deciding what consequences to draw.

"But this type of intelligence activities, with an assault as was planned in this case on another country's soil, is completely unacceptable," she said.

The Nordic prime ministers did not, however, want to let the terror plot influence their support for the 2015 nuclear deal with Iran.

Iran's foreign ministry has rejected the allegation that the country's intelligence services were behind plans for an attack on a group of Iranian residents, calling it a "conspiracy".

Nato drill

While concerned with both strategic foreign investments and Iranian plots, the five Nordic prime ministers downplayed risks from Russian military activity in their area.

Nato's biggest military manoeuvres since the Cold War kicked off last Thursday in Norway - also involving troops from the two non-Nato member countries, Finland and Sweden.

"It is important to show that a large amount of soldiers can cooperate, and for Norway it is important that they get a feeling of the Arctic climate. It is different, when there is snow and ice and not normal for many of the participants," Norway's Solberg said.

"The Russians have notified us, saying they would have a drill outside our borders. Of course, it is a response, of course, they are showing off, but on the other hand, it was something that we could expect," she said.

"It is also a message back home to Russia that we are reacting," she said.

"Russia is invited to observe Nato's exercise and I think we should take it a little bit more relaxed," she added.

The Swedish and Finnish prime ministers both insisted that their participation in the drill does not mean a change in their position as non-aligned countries.

"There is nothing strange in it, it is part of our normal program," said Finland's Sipila.

"It does not change the position of membership of Nato," said Sweden's Lofven.

Meanwhile the plenary, composed of members from all the Nordic parliaments, also focused on security concerns and discussed on Wednesday a concrete proposal for enhanced Nordic cooperation on cyber defences.