* Hazaras form a small but vocal minority in Afghanistan

* Some protesters throw stones, attempt to climb over blockades

* Protests pose a major challenge to Afghan government  

Some protesters threw stones and tried to climb over shipping containers stacked up to block the streets into Kabul's government and diplomatic areas but no significant violence was reported by mid-morning.

The demonstrators are demanding that the planned route for the 500 kV transmission line linking Turkmenistan with Kabul be changed to pass through two provinces with large Hazara populations, an option the government says would cost millions and delay the badly needed project by years.

As well as the potential for violence, the rally underscores the political tensions facing Ghani's government as it fights the Taliban-led insurgency and tries to get an economy shattered by decades of war back on its feet.

It follows one in November against the murder of a group of Hazara people that became the biggest anti-government demonstration in Kabul for years.

"We want our rights," said Abdul Rauf Safari, 35, a protester from Ghazni, a city in central Afghanistan with a large Hazara population.

"We will no longer accept discrimination and there is no way the government can ignore us this time," he said.

Organisers have urged protesters to "shake the palace of despotism". Authorities have closed access to the presidential palace, fearing a repeat of last year's violence, when demonstrators tried to scale the walls.

Rocks thrown

As marchers reached the roadblocks, some threw stones or banged on the sides of the metal containers but there was no immediate reaction from police. The bulk of the crowd then gathered in a square some distance from the city centre.

The mainly Shia Hazaras have long faced persecution but they are politically well organised.

Hazara leaders, who include senior government members, say the route chosen for the transmission line discriminates against their people, something President Ghani and national power company DABS deny.

Only around 30% of Afghanistan is connected to electricity. Modernising the creaking power system, which is subject to frequent blackouts, has been a top priority.

The transmission line, intended to provide secure power to 10 provinces, is part of the wider TUTAP project backed by the Asian Development Bank to link the energy-rich Central Asia republics of Turkmenistan, Uzbekistan and Tajikistan with Afghanistan and Pakistan.

Under current plans, due to be implemented by 2018, the line would pass from a converter station in the northern town of Pul-e-Khumri through the mountainous Salang pass to Kabul.

Demonstrators want an earlier version of the plan that would see a longer route from Pul-e-Khumri through the provinces of Bamyan and Wardak to the west of Kabul.

DABS says the current plan ensures ample power to Bamyan and Wardak and that switching the route would add tens of millions of dollars to the cost and delay the project by as much as three years, leaving millions without secure electricity.