Here is a timeline of the Ukraine events that led to the Trump impeachment inquiry

Source

House Speaker Nancy Pelosi on Tuesday said the House of Representatives will launch a formal inquiry into whether President Donald Trump should be impeached.

The Democratic-controlled House will examine whether Trump sought Ukraine's help to smear former Vice President Joe Biden, the frontrunner for the 2020 Democratic presidential nomination.

Here are some of the events that lead to the impeachment inquiry.

Reuters contributed to this report.