NATO must engage with Iran to secure regional support for the escalating war in neighboring Afghanistan, Secretary-General Jaap de Hoop Scheffer said Monday.

The call from the head of the Western alliance comes as the new U.S. administration of President Barack Obama prepares to send 30,000 more troops into Afghanistan, where Taliban militants are regrouping and violence is on the rise.

They will reinforce the 62,000-strong NATO and U.S. force already operating there.

"We need to stop looking at Afghanistan as if it were an island," de Hoop Scheffer said in a speech to the Security and Defence Agenda, a Brussels-based think tank.

"Afghanistan's problems cannot be solved by or within Afghanistan alone," he said. "There is a regional network of extremists … which respects borders no more than they respect human rights or the rule of law."

He said this would require adopting a broader approach that includes all of Afghanistan's neighbors.

"We need a discussion that brings in all the relevant players: Afghanistan, Pakistan, India, China, Russia — and yes, Iran. We need a pragmatic approach to solve this very real challenge," de Hoop Scheffer said.

Audience members asked de Hoop Scheffer to explain how Iran could be constructively brought into Afghanistan diplomacy, but he declined.

"I'm not sure at this stage what form that would take," he said.

The NATO chief warned that Western forces must prevail in Afghanistan. A Taliban victory, he said, would be "a disaster for international security and a legacy we cannot leave our children."

Until now, the United States has sought to isolate the clerical regime in Iran from meddling in Afghanistan, although the Shia nation has a long history of opposing Taliban rule there.

The differences between Washington and Tehran run deep. They include U.S. suspicions about Iran's nuclear program President Mahmoud Ahmadinejad's threats to annihilate Israel, and Tehran's support for the Palestinian militant group Hamas.