1.   Onlookers did not join them, a contrast to thousands who swelled an opposition march Thursday.

2.   Opposition marches to demand Chavez resign.

3.   Opposition march halted outside capital.

4.   But hundreds of riot police blocked an opposition protest march Friday.

5.   Chavez supporters have recently taken to the streets to confront opposition marches, sometimes at the urging of local authorities.

6.   In April, bloodshed at an opposition march triggered a coup that ousted Chavez for two days.

7.   In April, bloodshed at an opposition march triggered the coup.

8.   On Friday, Ortega accused pro-Chavez neighborhood associations known as Bolivarian Circles of ambushing the opposition march.

9.   Ortega accused pro-Chavez neighborhood associations known as Bolivarian Circles of ambushing the opposition march.

10.   One metropolitan policeman said he recognized federal district police officers in plainclothes among Chavez sympathizers who tried to storm an opposition march last month.