Prominent UP leaders in the fray in this phase are four members of Samajwadi Party patron Mulayam Singh Yadav's clan, besides senior party leader Azam Khan and actor-turned-BJP-candidate Jaya Prada.
The overall voting percentage was 60.52 per cent, UP's Chief Electoral Officer L Venkateshwarulu told reporters after polling closed at 6 pm. He said polling was held peacefully in the state.
There were complaints of electronic voting machines (EVMs) malfunctioning at some booths and they were promptly attended to, he had said earlier.
The SP lodged a complaint over the alleged malfunctioning of EVMs with the Election Commission, terming it criminal negligence.
According to a report from Sambhal, some EVMs developed snags in Chandausi and Asmoli assembly segments of the Aonla Lok Sabha seat.
In Pilibhit, polling at a sensitive booth in Kukrikheda started late by about an hour due to faulty EVMs.
At a booth in Etah zila panchayat, presiding officer Yogesh Kumar was removed after people accused him of forcing them to cast their votes in favour of the SP.
SP leader and former chairman of Bhargain Nagar Panchayat, Ahmed Nafis, was taken into custody in Kasganj in Etah after authorities anticipated breach of peace. He was to be placed in police custody till 6 pm, officials said.
SP MP Dharmendra Yadav, who is seeking re-election from Badaun, lodged a complaint against senior state minister Swami Prasad Maurya, claiming that he was campaigning in the constituency for his daughter and BJP candidate Sanghmitra Maurya.
But a raid at a house by district administration officials failed to locate him.
Poll rules bar party leaders from camping in a constituency after campaigning ends, unless they themselves are registered voters there.
The Uttar Pradesh seats where polling took place Tuesday are spread over the Rohilkhand region, where the BJP had won seven out of the 10 seats in 2014.
SP founder Mulayam Singh Yadav (Mainpuri) and nephews Dharmendra Yadav and Akshay Yadav (Badaun) and Akshay Yadav (Firozabad) are seeking re-election.
Pitted against Akshay Yadav, son of Mulayam Singh Yadav's cousin Ram Gopal Yadav, is Shivpal Yadav, another brother of the SP patriarch.
Shivpal Yadav floated a new political outfit, Pragatisheel Samajwadi Party (Lohia), after falling out with SP president Akhilesh Yadav.
In 2014, Mulayam Singh had won both the Mainpuri and Azamgarh seats, but vacated the first one, which was won by another family member Tej Pratap Singh in a by-election.
Senior SP leader Azam Khan is contesting from Rampur which witnessed a new low in campaigning this time with the controversial leader making a derogatory remark against BJP candidate Jaya Prada.
Other political heavyweights in Tuesday's test include Union Minister Santosh Kumar Gangwar, who is fighting from Bareilly and BJP's Varun Gandhi from Pilibhit.
Altogether 1.76 crore voters were eligible to exercise their franchise in this phase at 20,116 polling booths. Some 120 candidates are in the fray for the 10 seats.
With three polling phases nationwide over now, voting has taken place in 26 of the 80 Lok Sabha constituencies in Uttar Pradesh.
The Bharatiya Janata Party here faces an alliance of the Samajwadi Party, the Bahujan Samaj Party and the Rashtriya Lok Dal.