At least seven people have been killed and scores wounded in clashes between government troops and Maoists in Nepal, reports say.
The fighting took place on Thursday when the rebels attacked an army convoy in south-western Nepal.
The BBC's Sushil Sharma says the clashes appear to be one of the heaviest in recent months.
The violence follows Wednesday's controversial local elections in which 20% of voters cast their ballots.
The Nepalese army says two of its soldiers died in the latest fighting which is also said to have claimed the life of a civilian.
"Clashes began in Nawalparasi district Thursday afternoon and lasted until around 7pm," an unnamed army official is quoted as saying by the AFP news agency on Friday.
Violence has escalated in Nepal over the past month
The rebels have confirmed the loss of four fighters.
Our correspondent says details are awaited from the site amid fears of heavy casualties on both sides.
Eyewitnesses say they could see some billowing from some damaged army vehicles on the key Mahendra highway leading to the capital, Kathmandu.
A rebel leader also says 12 soldiers and a number of guns have been seized but this cannot be independently verified.
Violence has escalated across Nepal after the rebels called of a four-month unilateral ceasefire last month.
The government had refused to reciprocate the truce, saying that they could not trust the rebels.
The rebels also called a four-day general strike in Nepal earlier this week, to disrupt local municipal elections.
The elections, which were also opposed by the opposition, had been called by King Gyanendra who has also pledged to hold national elections next year.
But the opposition says the king was attempting to legitimise his rule, after seizing direct power in 2005.
Some 13,000 people have died in the Maoist insurgency which completes 10 years next week.