Fighting between government forces and the Taliban has been particularly heavy around the city of Herat, near the western border with Iran, and Lashkar Gah and Kandahar in the south.
The United Nations is 'deeply concerned' about the safety and protection of tens of thousands of people in Afghanistan's southern Helmand province who could be trapped by fighting between government forces and the Taliban.
"Since the start of the year nearly 360,000 people have been forcibly displaced by the conflict in Afghanistan. About 5 million people have been displaced since 2012," UN spokesman Stephane Dujarric told reporters on Wednesday.
The Taliban have stepped up their campaign to defeat the US-backed government since April as foreign forces complete their withdrawal after 20 years of war.
Fighting has been particularly heavy around the city of Herat, near the western border with Iran, and Lashkar Gah and Kandahar in the south.
"We're deeply concerned about the safety and protection of people in Lashkar Gah, in the south, where tens of thousands of people could be trapped by the fighting," Dujarric said.
He also said in Helmand and Kandahar "there are reported increased civilian casualties, destruction or damage to civilian houses, as well as to critical infrastructure and hospitals".
Helmand province's hospital chief, Sher Ali Shakir, urged people to remain in their houses on Wednesday, saying that in past 24 hours at least seven civilians were killed and 101 were wounded.
Afghan officials on Wednesday said US and Afghan airstrikes have hit Taliban targets overnight in Helmand province in an effort to push back the insurgents after they captured much of the provincial capital, Lashkar Gah
They have taken large swaths of land and have now turned their guns on larger urban centers.
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After a night of heavy airstrikes, the Defense Ministry said on Wednesday that the Taliban have suffered heavy losses in Lashkar Gah, though there was no immediate way to confirm that statement.
A Taliban spokesman denied the losses.
Afghan authorities did not say whether Afghan forces have retaken back territory.
The fall of Lashkar Gah would be a major turning point in the Taliban offensive and it would also be the first provincial capital to be captured by the insurgents in several years.
Along with Lashkar Gah, the provincial capitals of Herat, in western Herat province, and Kandahar, in southern Kandahar province have also been under Taliban attack.
The fighting in Herat in the last week has has killed 34 people and wounded more than 150, said physician Mohammad Aref Jalali, the provincial hospital chief in Herat.