Two passenger trains collided in southern Pakistan Monday, killing at least 35 people and wounding dozens of others, per AP.

The big picture: Up to 20 people remained trapped in the Millat Express train after the collision with the Sir Syed Express in Ghotki district in Sindh province, AP reports.

• Prime Minister Imran Khan tweeted that he has asked the Railways minister to go the the crash scene to oversee rescue operations, adding he has ordered a "comprehensive investigation into railway safety fault lines."

Editor's note: This a breaking news story. Please check back for updates.