Taliban fighters have attacked a police headquarters in southern Afghanistan, killing 20 security personnel and seizing three army checkpoints, Al Jazeera has learnt.

Al Jazeera's Jennifer Glasse, reporting from Kabul on Tuesday, said fighting was going on in three areas of Helmand province, with clashes raging in the districts of Sangin, Musa Qala and Nawzad.

"In Nawzad, the standoff has been particularly difficult and has been going on for hours with the Taliban taking three army checkpoints and surrounding the district's headquarters," she said.

"At least 20 army and police officers have been killed in that attack, and local officials have called for reinforcements."

Thirteen of the victims were police officers and seven were soldiers.

Fighting was also reported in the southern province of Kandahar.

Meanwhile, in the eastern province of Wardak, four suicide bombers attacked a local court, with all four of the assailants reported killed, along with two police officers.

The Taliban has launched a wave of attacks around the country since the withdrawal of foreign troops last year.

The group claimed responsibility for an attack on a Kabul guesthouse earlier this month that left 14 people dead, including nine foreigners.

According to the United Nations Assistance Mission in Afghanistan (UNAMA), in the first three months of 2015, civilian casualties from ground fighting were up eight percent on the same period last year.

Source: Al Jazeera