KABUL, Aug 15 (DW) - The Taliban, an Islamist militant group that has seized large parts of Afghanistan, have started entering the outskirts of Kabul on Sunday, local officials said.

The Afghan capital is the last major city held by government forces. Gunfire and sirens were heard sporadically across Kabul.

The militant group later pledged not to take the capital "by force."

"No one's life, property and dignity will be harmed and the lives of the citizens of Kabul will not be at risk," the Taliban said in a statement.

But Matin Bek, the chief of staff to Afghan President Ashraf Ghani, wrote on social media: "Don't panic! Kabul is safe!"

The Taliban started an offensive nearly two weeks ago, capturing a number of key towns, cities and border posts.

Sunday's move on Kabul comes as international forces prepare to evacuate their diplomats amid the worsening security situation.

US intelligence officials said earlier this week that they believed it might take as long as three months for the Taliban to seize the Afghan capital.