A hacking team behind an advanced persistent threat (APT) cyber espionage campaign dubbed Pawn Storm that has been targeting U.S. military, embassy, and defense contractor personnel for the past several years, has stepped up its attacks in recent weeks.

In an update this week, security firm Trend Micro, which first reported on the threat last October, said the group behind Pawn Storm has been busy setting up dozens of new exploit URLs and command and control servers since the beginning of the year.

Among the group’s targets are members of the White House and the North Atlantic Treaty Organization (NATO) as well as governments in Europe, Asia and the Middle East. Many of the group’s targets include Russian dissidents and those opposed to the Kremlin, suggesting it has ties to the Russian government, the security firm says.

“Geopolitics serve as harbingers for cyber attacks,” says Tom Kellermann, chief cybersecurity officer at Trend Micro. “Hackers sympathetic to Russia have escalated a campaign of hacking targeting the US government; NATO and Ukraine.”

The attackers are also targeting journalists who are critical of the Russian regime, he says, adding that thousands of individuals have been selectively targeted over the past several months.

The group behind Pawn Storm has been active since at least 2007 and has used a combination of malware-laden spear-phishing emails, watering-hole attacks, and spoofed Microsoft Outlook Web Access login pages to infiltrate systems belonging to a very highly targeted set of victims. The apparent goal behind the campaign is economic and political cyber-espionage. Victims have included defense contractor ACADEMI (formerly Blackwater), SAIC, and the Organization for Security and Cooperation in Europe. The most recent targets have included members of the White House and journalists.

The reporters that have been targeted include three popular YouTube bloggers who had interviewed President Obama at the White House earlier this year, as well as a military correspondent for a large U.S. newspaper, Trend Micro said.

According to Kellermann, in addition to an increase in the volume of attacks, Trend Micro researchers have also observed an increasing sophistication in the attack campaign.

A lot of the malware that is being dropped on victim systems are highly pared down and appear designed largely for fingerprinting the systems for the purpose of targeting them with more sophisticated payloads later. For example, there are no backdoors and keyloggers on the malware that the group initially installs on targeted systems.

Instead, a lot of the focus appears to be on stealth and remaining undetected. “We are seeing a refinement—almost a minimization of capabilities for the purposes of obfuscation,” with the latest wave of attacks, Kellermann says. What is also interesting is that the latest payloads have a built-in timing mechanism to delay code execution so as to evade sandboxing tools, he says.

In addition to the original list of victims, Pawn Storm has also begun going after a wider but still focused group of victims. The targeting suggests that the perpetrators of Pawn Storm have begun focusing on people who are one-degree separated from their actual targets, he says.

Many data breaches in recent months, including those at Sony Pictures, the U.S. State Department and the White House have been blamed on supposedly state-sponsored hacker groups like Pawn Storm.

The Sony attack for instance, was pinned on hackers apparently operating at the behest of the North Korean government in response to a movie satirizing the country’s leader Kim Jong Un. Just last week, Russian hackers were blamed for the State Department and White House attacks last October, apparently in retaliation for the U.S.-led economic sanctions against the country.

Security experts in the past have noted that the enormous difficulty involved in attributing an online attack with certainty to a particular source can often lead to mistaken assumptions about the true origins of an attack.