At least 20 civilians died in Syrian regime strikes on targets including schools, a monitor said Tuesday, in a relentless advance on the country’s last major opposition holdout that saw loyalists seize a symbolic town. Pro-regime bombing killed at least nine children, the Syrian Observatory for Human Rights said, as Russian-backed regime forces wage a fierce offensive to seize Idlib, the final major territory in Syria still controlled by rebels and jihadists. Regime strikes in Idlib, the main city in the densely populated, ever-shrinking enclave of the same name, killed a schoolchild and three teachers as well as two others, said Observatory head Rami Abdel Rahman.