BEIRUT (AP) — Government forces on Wednesday seized vast swathes of territory including farmland from rebels in the opposition-held suburbs of Damascus, effectively dividing the besieged enclave in two and further squeezing rebels and tens of thousands of civilians trapped inside, state media and a war monitor reported.

The government, determined to wrest the suburbs from the control of rebels after seven years of war, has resorted to extreme levels of shelling and bombardment to clear the way for its troops to advance on the ground. Hundreds have been killed in the past two weeks.

The state-a...