The phrase "undermine relations" is grammatically correct and can be used in written English.
It means to weaken or damage relationships between people or groups. Example: The constant bickering and negative remarks between the two colleagues only served to undermine relations in the workplace.
Withdrawal would also undermine relations with China.
It also marks a triumph for President Hamid Karzai, who has repeatedly stressed that civilian casualties undermine relations between the countries.
"Without question there are GoE officials who do not want a close relationship with the US and are actively working to undermine relations.
But Mr. Karzai has emphasized how civilian casualties undermine relations between the countries and has often pushed for a less confrontational approach in dealing with the Taliban.
The careful wording of the comment reflected South Korea's fear that missile defense might undermine relations with China and Russia, North Korea's strongest allies in the Korean War.
NATO officials and Western diplomats here have been steeling themselves for the release, worried that it will further undermine relations with President Hamid Karzai at a sensitive time when there have been several recent episodes of civilian casualties.
It severely undermined relations between the US and Pakistan.
The legacy of displacement during the rule of Saddam Hussein's Sunni Baathists has further undermined relations.
Calais business leaders claim it has detroyed tourism, and undermined relations between northern France and south-east England.
It is the latest in a series of incidents that have undermined relations between Ankara and Washington since the US-led air campaign against Isis began in late 2014.
"This is understandable because it undermines relations with Russia, but it's not acceptable because relations were undermined not by Marina Litvinenko [in pressing for the inquiry] but by the people who murdered her husband in the first place".
