Danish Prime Minister Lars Lokke Rasmussen called the planned attack "totally unacceptable" and British Prime Minister Theresa May had voiced her support for Denmark during a meeting in Oslo. "Further actions against Iran will be discussed in the European Union", the PM tweeted.
The suspect was seen taking photos of the residences of members of the Arab Struggle Movement for the Liberation of Ahwaz (ASMLA) in Ringsted, a town almost 60 kilometers (37 miles) southwest of Copenhagen, Borch Andersen said.
ASMLA seeks a separate state for ethnic Arabs in Iran's oil-rich southwestern province of Khuzestan.
"We congratulate the government of Denmark on its arrest of an Iranian regime assassin. Obviously, we can't and won't accept that", Mr Samuelsen said.
A Norwegian citizen of Iranian origin was arrested in Sweden on 21 October in connection with the alleged plan.
Samuelsen said that recalling an ambassador was unusual and it had been done by the Danes perhaps only once before.
The terror attack on the military parade in the Iranian city of Ahvaz.
In a ministry statement issued earlier in the day, Samuelsen said that the Iranian ambassador in Copenhagen had been summoned to the foreign ministry.
"As stated by the head of the Danish Security and Intelligence Service earlier today, the assessment is that an Iranian intelligence agency has planned an assassination on Danish soil".
'This is completely unacceptable. It's completely unacceptable. Actually, it's hard to describe how serious this case is.
The Foreign Ministry says it will be discussing "the issue of an Iranian intelligence agency's illegal activities in Europe" with worldwide allies.
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It was spotted on October 2 in the eastern part of the Kagem mine, where a team of miners has found luck in the past few months. For years, Gemfields had a pineapple-sized emerald locked in a safe as it didn't know how much it was worth.
Norwegian police have confirmed they are assisting the Danish officers in their inquiries.
The attack was meant to target the leader of the Danish branch of the Arab Struggle Movement for the Liberation of Ahvaz (ASMLA), Danish intelligence chief Finn Borch Andersen said.
Finn Borch Andersen said police on September 28 were searching for a stolen, Swedish-registered vehicle when they briefly cut off the island where Copenhagen sits from the rest of the country and closed the borders with Germany and Sweden. They later found it had no connection with the case.
Finn Borch Andersen, head of the Danish Security and Intelligence Service.
In May, the U.S. secretary of state, Mike Pompeo, claimed that Iran's Revolutionary Guard was carrying out "assassination operations in the heart of Europe", an allegation that at the time bewildered security experts, given that there had been no recent killings in Europe officially attributed to the Iranian state. ASMLA condemned the violence and said it was not involved. The country will respond and speak with European partners about "further steps", he said on Twitter, without elaborating.
Three members of ASMLA remain under Danish police protection, as the "threats have not been eliminated", Andersen said.
Iran blamed ASMLA for carrying out an attack at the end of September which targeted an Iranian military parade, leaving at least 29 people dead and wounding more than 70 others.
Iranian foreign ministry spokesman, Bahram Qasemi, dismissed the accusations.
He emphasized that these claims are the continuation of plots and conspiracies hatched by known enemies who are against good and expanding Iran-Europe relations at the current sensitive conditions.
The so-called Islamic State group and a separatist Arab group claimed responsibility, and Iran staged several operations in Iraq and Syria in response.
Denmark has recalled its ambassador to Iran after it accused Tehran of plotting a foiled "attack" against three Iranians living in the Scandinavian country.