After a slow start, voting picked up in constituency after constituency, Election Commission officials said.
An estimated one crore people are eligible to vote on Thursday. Average voting in the first four hours ranged from 23 per cent at Kaushambi to 35 in Allahabad.
Other places which saw brisk or high voting included Mahoba, Jhansi, Chitrakoot, Lalitpur and Rae Bareli, the Lok Sabha seat of Congress President Sonia Gandhi.
Officials also reported long queues of men and women voters in Fatehpur, the Lok Sabha constituency of union minister Sadhvi Niranjan Jyoti, Jalaun and Hamirpur.
Skirmishes erupted in Pratapgarh between Bharatiya Janata Party (BJP) and Bahujan Samaj Party (BSP) activists and in Mahoba between workers of the ruling Samajwadi Party and the BSP.
Prominent among those who voted early were West Bengal Governor Keshari Nath Tripathi, BJP state chief Keshav Prasad Maurya, union minister Niranjan Jyoti, Congress leader Pramod Tiwari and his daughter Aradhana Mishra, the Congress candidate from Rampur Khas in Pratapgarh.
Samajwadi Party candidate Siddha Gopal Sahu’s son was shot and seriously injured at Mahoba.
In Bundelkhand region, people boycotted polling in some villages.
The fourth phase is especially significant for the Congress as it won only six seats from among these constituencies in 2012.
This time, the Congress has struck an alliance with the Samajwadi Party — the two parties are contesting 298 and 105 seats each.
Electronic Voting Machines developed snags in at least a dozen places, disrupting balloting.
A total of 680 candidates are in the fray, including 61 women. But the main battle is between the BJP, the BSP and the Samajwadi Party-Congress alliance.
The seven-phase Uttar Pradesh election began n February 11 and will end on March 8. The results from the state as also Punjab, Goa, Uttarakhand and Manipur will be known on March 11.