The city of Jerusalem and the Interior Ministry said they had carried out separate demolitions over the past 48 hours of houses built in areas zoned for open green space.
Field workers for the B'Tselem human rights group documented demolitions of five houses and a gas station on Monday, and of another three houses on Tuesday, said the group's spokeswoman Sarit Michaeli.
Several of the houses were still under construction, but most were finished, she said. Palestinians said it was quite impossible for them to obtain permits to build houses and therefore many houses were built without them.
"It's very worrying," Michaeli said. "This has to be viewed in light of the complete inability of Palestinians in East Jerusalem to get building permits. It is not just a matter of the law."
Meir Margalit, an activist with the Israeli Committee Against House Demolitions, said thousands of homes in Jerusalem still had outstanding demolition orders.
He feared a surge of demolitions while attention is focused on Israel's planned withdrawal from the Gaza Strip as of mid-August.
A spokesman for Jerusalem said the city had razed 37 structures so far this year, compared to 124 for 2004, but gave no information on plans for further demolitions.
B'Tselem says house demolitions have increased in East Jerusalem since September 2000.