Bild newspaper says interior ministry emphasising the need for effective counter-intelligence in wake of arrest of BND staffer

Germany may step up its counter-espionage efforts after an employee of its intelligence service was arrested on suspicion of spying for the US.

Measures being considered in response to scandal include monitoring the intelligence activities of nominal Nato allies such as America, Britain and France, as well as expelling US agents from Germany.

According to a report in Bild, the interior minister, Thomas de Maizière, has emphasised the urgent need for a "360 degree vision" of the foreign secret agency's activities. The newspaper claims to have obtained an internal document which outlines "concrete counter measures", thus moving away from a policy of not spying on Nato allies.

Asked about the new policy, a spokesperson of the German interior ministry did not deny the reports and said "an efficient and effective counter-intelligence against all sides is important, necessary, and has to be better organised than it has until now."

On Wednesday, Germany's federal prosecutor had arrested a 31-year-old employee of the German intelligence agency (BND) on suspicion of having sold secret documents to a contact at the CIA.

The BND staffer, a technical support worker employed in a unit dealing mainly with the protection of German soldiers abroad, is alleged to have established contact with the American secret service by contacting the US embassy. Rather than report the contact to their allied German counterparts, the CIA is reported to have paid the agent €25,000 (£20,000) for 218 documents classified as confidential or top secret .

In a press conference on Monday, government officials declined to comment on the affair, but a number of high-ranking politicians and officials have expressed their outrage, with one member of Angela Merkel's party suggesting that US agents should be expelled from Germany.

"If it emerges that the BND employee was really directed by American agents on German soil, then it would be hardly comprehensible if US employees could continue to do harm over here," Karl-Georg Wellmann of the CDU told Spiegel Online.

But the German lawyer of NSA whistleblower Edward Snowden said the German government was using the latest scandal to point the finger at the NSA and redistribute resources to its own intelligence service rather than draw genuine political consequences.

Speaking at a press conference with foreign media in Berlin, Wolfgang Kaleck said: "The NSA alone isn't the issue. The way all European nations conduct spying operations must be reviewed.

"One would have hoped for a more spontaneous reaction on behalf of the government, such as a different approach to the issue of Snowden's asylum," Kaleck said. "It doesn't look like they want to do that. But it shows that the Snowden case isn't finished."

Konstantin von Notz, a member of the parliamentary investigation committee into the NSA activity, also criticised the government's reaction: "To respond to these allegations with the motto 'now we're going to spy back on you' is just absurd, and a sign of the government's helplessness. Either these surveillance activities are illegal and we do something to curb them, or not."

"If the German government wanted to apply real pressure on the US, it would do something about [the trans-Atlantic trade agreement] TTIP or the Safe Harbor directive," he said.

The German president, Joachim Gauck, said if the allegations were to turn out to be true, it would amount to "gambling with friendships and close alliances".

"Then it truly needs to be said: enough is enough," he added.

In a talk show on Sunday night, the defence minister, Ursula von der Leyen, made a personal appeal to the former US secretary of state Hilary Clinton: "For God's sake, take a hard line with your secret services," adding: "Good friends don't spy on one another."

The chancellor, Angela Merkel, has been more guarded in her reaction, telling a news conference during her current trip to China: "If the reports are correct it would be a serious case."