Chief Constable Dee Collins said there would be extra officers on the streets of West Yorkshire today, including armed officers at key locations such as transport hubs.
She said in a statement: “In such a tragic and terrible time the thoughts of everyone connected with the Force are with all those who lost their life or were injured during the explosion and for the family members and friends who lost a loved one.
“We stand shoulder to shoulder with the people of Manchester and our colleagues in Greater Manchester Police and we have provided practical support to the Force.
“Emergency numbers have been established for anyone who is concerned for loved ones who may not have returned home 0161 856 9400 or 0161 856 9900.
“The public’s safety remains our top priority and we have already increased patrols of highly visible officers across West Yorkshire. This includes an increase in armed officers at key locations including transport hubs.
“This is a concerning time and I hope that our increased presence helps to reassure the public that we are working with our partners to do everything we can to protect the security of the communities we serve.
“Likewise I would urge our communities to come together and show our strength in unity.
“If you have any concerns or see anything suspicious I would urge you to report it immediately to the Confidential Anti-Terrorist Hotline on 0800 789321. In an emergency always dial 999.
“The easy-to-remember national guidance of Run, Hide, Tell, explains what people should do if they are confronted by terrorists. First ‘Run’ to a place of safety. This is a far better option than trying to surrender or negotiate. If there is nowhere to run then ‘hide’.
“It is better to hide than confront. Remember to turn your phone to silent and turn off vibrate. Barricade yourself in if you can. Then finally, and only when it is safe to do so, ‘tell’ by calling police on 999”.