/euronews/  Security is now tight around a prison in Mexico after a brazen escape by scores of inmates. Soldiers and federal police are surrounding the jail in Nuevo Laredo, but it has come too late after 140 prisoners walked out in broad daylight from the prison on the border with Texas.

The state's security chief has confirmed the escapees made their way out via the service entrance after being helped by staff on the inside.

The jail's director is said to be missing.

The head of the state's prison system has been suspended.

This latest escape follows a string of security breaches at jails across northern Mexico.

Heavily-armed police are carrying out roadchecks in a bid to recapture the escapees.

It is not clear who is behind the break, but police believe a drugs cartel may have freed some other gang members on condition that they switch sides.