A Franson-type test of the Bell-inequality is presented. Energy and time entangled photons at a wavelength of 1310 nm are produced by parametric downconversion in a KNbO3 crystal and are sent into all-fiber interferometers using a telecom fiber network. The two interferometers are located 10.9 km aside from one another. Two-photon fringe visibilities of up to 81.6 % are obtained. These strong correlations yield a violation of Bell's inequality by 10 standard deviations thus confirming the nonlocal predictions of quantum mechanics.