After updating IntelliJ from version 12 to 13, the following Maven-related plugins cannot be resolved:
org.apache.maven.plugins:maven-clean-plugin:2.4.1 org.a
I was recently faced with the same issue. None of the other solutions resolved the red error lines.
What I did was run the actual targets in question (deploy, site). I could see those dependencies then being fetched.
After that, a reimport did the trick.