A suspect package is being investigated at a site where coronavirus vaccines are manufactured.
Global pharmaceutical and biotechnology company Wockhardt, which provides fill-and-finish for Covid-19 vaccines, said the company’s site in Wrexham has been “partially” evacuated.
Police officers and a bomb disposal unit are at the scene.
A spokeswoman for the company said: “Wockhardt UK in Wrexham this morning received a suspicious package.
“All relevant authorities were immediately notified and engaged. Upon expert advice we have partially evacuated the site pending a full investigation. The safety of our employees and business continuity remains of paramount importance.”
A spokesman for North Wales Police said: “We are currently dealing with an ongoing incident on the Wrexham Industrial Estate.
“The roads are currently closed and we would ask the public to avoid the area until further notice.”
A spokeswoman for the Ministry of Defence said an explosive ordnance disposal team based in Chester was called out just after 11.30am and was assisting the authorities in Wrexham.
Downing Street is being kept up to date on developments, a Number 10 spokesman said.
Dave Picken, 53, who lives near Wrexham Industrial Estate, said: “We’ve seen lots of police cars and a fire engine.
“Bomb disposal are here with a robot.
“We were closer to the factory but police told us to move and cordoned off a bigger area.
“I did ask an officer how big the bomb is but he said he couldn’t say it’s a bomb.”
Last week, emergency teams were called out to protect supplies of the Oxford University and AstraZeneca coronavirus vaccine following flooding at the industrial estate.
All “necessary precautions” were taken to prevent disruption to the manufacture of the jab, a Wockhardt spokeswoman said at the time.