MOSCOW, March 16 (Reuters) - Russia accused Ukraine on Saturday of using "terrorist activities" to try to disrupt its presidential election and former President Dmitry Medvedev decried as "traitors" the scattered protesters who have tried to set fire to voting booths and pour dye into ballot boxes.

The Ukraine war has cast a shadow over voting in the election, which is all but certain to hand President Vladimir Putin six more years in the Kremlin but has been marked by sporadic acts of protest.

On the second of three days of voting, the Russian foreign ministry said Kyiv had "intensified its terrorist activities" in connection with the election "to demonstrate its activity to its Western handlers and to beg for even more financial assistance and lethal weapons".

It said that in one such incident, a Ukrainian drone had dropped a shell on a voting station in a Russian-controlled part of Ukraine's Zaporizhzhia region.

The state-run TASS news agency quoted a local election official as reporting no damage nor injuries when the explosive device landed five or six metres (yards) from a building housing a polling station before it had opened in a village about 20 km (12 miles) east of the city of Enerhodar.

Reuters could not independently verify the incident.

There was no immediate comment from officials in Ukraine, which regards the election taking place in parts of its territory controlled by Russia as illegal and void.

Meanwhile the head of the electoral commission, Ella Pamfilova, said that in the first two days of voting there had been 20 incidents of people trying to destroy voting sheets by pouring various liquids into ballot boxes, as well as eight cases of attempted arson and a smoke bomb.

Commenting on the incidents, Medvedev said those responsible could face treason sentences of 20 years.

"This is direct assistance to those degenerates who are shelling our cities today," he posted on social media, referring to Ukrainian attacks.

On Sunday's final day of voting, supporters of late opposition leader Alexei Navalny have called on people to turn out en masse at noon in a rolling protest against Putin in each of the country's 11 time zones.

Photo from Reuters