Afghan authorities have closed off streets across the capital, Kabul, in preparation for a demonstration by ethnic Hazaras demanding a planned power line be rerouted through their poverty-stricken province.
Police have been moving trucks and containers into the city overnight Friday to block roads and prevent marchers reaching the city center or the presidential palace.
It is the second march against the current route of a multi-million-dollar regional electricity line. The last one in May attracted tens of thousands.
The so-called TUTAP line is backed by the Asian Development Bank with involvement of Turkmenistan, Uzbekistan, Tajikistan, Afghanistan and Pakistan. The original plan routed the line through Bamiyan province, in the central highlands, where most of the country's Hazaras live.
That route was changed in 2013 by the previous Afghan government.