The Islamic State group is changing its tactics, counterterrorism officials in the U.S. and Europe said this week, by borrowing from the playbook of older terror groups that favored larger, more coordinated plots against the West. The officials point to the shooting and bombing attacks in Paris one week ago as the most visible evidence of ISIS' new approach.

Their analysis is based on intercepted communications and other intelligence gathered after the large-scale attacks in Beirut on Nov. 12 and Turkey on Oct. 10, launched by the Islamic State group, or ISIS, in Syria and Iraq and carried out by foreign recruits, the Wall Street Journal reported. The terror group has “been anxious to make this shift for a long time,” Bruce Hoffman, a Georgetown University professor who has studied terror networks, told the Journal.

“It’s a learning curve” for Islamic State leaders looking to build a more sophisticated infrastructure, Hoffman added. But the main goal of the group hasn’t changed – they want to build a caliphate in the Middle East and launch attacks against their Western enemies, counterterrorism officials said.

Some said the strategy shift for the Islamic State mirrors an al Qaeda model of more-elaborate attacks. But this could make Islamic State plots easier to detect and foil, as the more people involved in a plot, the more likely investigators can learn about it in advance.

Even with the apparent operational changes, ISIS continues to show operational care, flexibility and secrecy that makes the terrorist group dangerously effective, the Journal reported. Their use of encrypted communication technologies has been an intensified focus of investigators since last week's Paris attacks.

The Islamic radicals from Europe have been moving in and out of Syria along routes used by unaffiliated organized-crime gangs, who ship weapons and drugs across the continent, European officials said. This makes it easier for ISIS to deploy trusted lieutenants throughout the world. However, U.S. counterterrorism officials contend that Islamic State lieutenants have not slipped into the U.S.