Iran and Saudi Arabia are recruiting and radicalizing local Muslim populations in Afghanistan, India, and Pakistan.

Almost 3 years into Rouhani’s drive to normalize Iran’s relationships with its neighbors, Iran is as isolated as ever.

Xi Jinping tries to deepen ties with Iran, while not alienating Saudi Arabia.

By keeping a tight focus on bilateral ties, China hoped to avoid upsetting Iran during Xi's first trip to Saudi Arabia.

For the religious rivals, Afghanistan is another front in the fight for influence.

A planned trip in 2015 was scuttled due to regional tensions. Will Xi's 2016 Middle East tour share the same fate?

China sends an envoy to Riyadh and Tehran to discuss the latest flare-up in tensions.

The early 1970s offers some interesting parallels.

Growing sectarian conflict elsewhere has worrying implications for Afghanistan.