  We give stability estimates in the Cauchy problem for general partial
differential equation of the elliptic type similar to the Helmholtz equation.
We do not impose any (pseudo)convexity assumptions on the domain or the
operator. These conditional stability estimates are getting close to Lipschitz
ones when the wave number/frequency is growing. We split solution into low and
high frequency parts and impose constraints on the high frequency part only. We
give logarithmic bounds on this high frequency part. Proofs use energy
estimates and the FBI transform.
