Police in Hong Kong have clashed with pro-democracy protesters as they tried to clear an underpass near the city government headquarters.

Police said in a statement that complaints of excessive use of force by officers would be investigated

Hundreds of police officers wearing riot gear used pepper spray and batons to disperse the protesters, arresting dozens of people in the process.

At a briefing before the clashes, police said they had to clear Lung Wo Road as it was a major thoroughfare.

Demonstrators have occupied parts of Hong Kong for more than two weeks.

The protesters, a mix of students and a pro-democracy group called Occupy Central, are demanding fully free elections in the next vote for the territory's leader.

China, which has control over Hong Kong, says residents can vote - but it will vet which candidates are eligible to stand.

The BBC's Juliana Liu in Hong Kong says violent clashes have been a rare sight since the evening that tear gas was first used at the beginning of the pro-democracy protests.

Their new advance came when protesters blockaded the underpass after being cleared out of other areas of the city on Tuesday.

Local television networks broadcast live footage of scuffles, showing police arresting many protesters, whose hands were tied with plastic cuffs.

'Punches, kicks, elbows'

Tsui Wai-Hung, a police spokesman, said 37 men and eight women had been arrested for "unlawful assembly".

None of those arrested had been hurt, the spokesman insisted, but four police officers were said to have been injured.

However, footage shown on local station TVB appeared to show one protester being taken aside by police officers and beaten.

Daniel Cheng, a journalist reporting on the clashes, told the AFP news agency that he was also beaten up by police officers.

"[Police] grabbed me, more than 10 police, and they beat me: punches, kicks, elbows. I tried to tell them I'm a reporter but they didn't listen."

The police later issued a statement saying complaints of excessive use of force by officers in this incident would be investigated.

The protesters are now in their third week of occupying key parts of the city in a bid to put pressure on China and Hong Kong's authorities to answer their calls for reform.

Thousands of people took to the streets at the beginning of the demonstrations but the numbers have dwindled in recent days.

Over the weekend, Hong Kong's embattled leader CY Leung said the protesters had zero chance of changing Beijing's mind on constitutional reform, saying the protests had spun out of control.

Source: BBC