US President Barack Obama. Pic: AP.

WASHINGTON (AP) — President Barack Obama says the U.S. and China must improve their communication and coordination to address the nuclear threat from North Korea.

Obama and Chinese President Xi Jinping (shee jihn-peeng) spoke by phone on Monday. The U.S. has been pressing China, North Korea’s most powerful ally, to take a harder line against the North’s nuclear program.

The White House says Obama and Xi will meet in November at a regional economic summit in Beijing.

The two leaders also discussed cooperation between the U.S. and China on the Iranian nuclear issue. Obama told Xi that Iran must take steps to prove its nuclear program is peaceful.

The White House says Obama also told Xi he’s committed to constructive management of differences between the U.S. and China.