Cotton futures fell on Friday, as lack of clarity about progress on a US-China trade deal weighed on investor sentiment, while the Democrats' latest impeachment move against President Donald Trump further added to the uncertainty in the market.

Cotton contracts for March fell 0.46 cent, or 0.68%, at 66.71 cents per lb by 1 pm EST (1800 GMT), trading within a range of 66.43 and 67.8 cents a lb. However, with gains of more than 2.5% so far this week, the natural fiber is on track for its best week in two months.

“The main factor is that even though they (US and China) agreed to a ‘phase one' trade deal … they are still trying to figure out the details on the commodities which China will be purchasing," said Bailey Thomen, cotton risk management associate with INTL FCStone.

Also, “Presidential impeachment was passed in the (House of Representatives Judiciary) committee this morning, so there is a little bit of pessimism in the market."

The United States agreed to modify its tariffs on Chinese goods in a “significant way" under a “phase one" trade agreement with Beijing, while China would buy substantially more US goods and services, the US Trade Representative's office said on Friday.

China and the United States have agreed on the text of a phase one trade deal, and Beijing has decided to cancel an earlier plan to impose additional tariffs on US imports on December 15, senior Chinese government officials said. The Democratic-controlled House Judiciary Committee approved charges of abuse of power and obstruction against Trump, a Republican, on Friday, making it almost certain he will become the third American president in history to be impeached.

Total futures market volume fell by 6,461 to 39,065 lots. Data showed total open interest gained 5,627 to 200,691 contracts in the previous session. Certificated cotton stocks deliverable as of December 11 totaled 25,354 480-lb bales, down from 27,057 in the previous session.