BROOKLYN, N.Y. (PIX11) — A man walked into a hospital in Brooklyn with stab wounds across his body, police said on Monday.

Authorities believe the attack happened on Graham Avenue around 4:40 a.m. The 30-year-old victim then walked into NYC Health + Hospitals/Woodhull, located just down the block, with stab wounds to his leg and upper chest.

Police described his condition as critical. The circumstances that led to the stabbing remained under investigation. No arrests had been made, as of Monday morning.

Submit tips to police by calling Crime Stoppers at 1-800-577-TIPS (8477), visiting, downloading the NYPD Crime Stoppers mobile app, or texting 274637 (CRIMES) then entering TIP577. Spanish-speaking callers are asked to dial 1-888-57-PISTA (74782).