Afghan officials said Tuesday that a coordinated militant attack was underway in the city of Jalalabad, the capital of eastern Nangarhar province. Zabihullah Zemarai, a member of the provincial council, said there was first a car bombing -- likely an explosion set off by a suicide car bomber -- near the city's provincial hospital and health department on Tuesday, followed by gunfire.

He said a refugee and repatriation department is also located in the same area of the city so the immediate target wasn't clear. Zemarai couldn't confirm any casualties but said a heavy gunbattle was taking place between Afghanistan's security forces and the attackers.

Attaullah Khogyani, a spokesman for the Nangarhar provincial government, confirmed to CBS News that a complex attack was underway, appearing to target a building of the department of immigration and refugees in Jalalabad city. Khogyani said security forces had arrived at the scene and that the director of the department along with some employees had been rescued.

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The Reuters news agency reported that many employees of the immigration office had been taken hostage by the militants in Jalalabad, but police did not immediately confirm the report.

No one immediately claimed responsibility for the attack but both the Taliban and the Islamic State of Iraq and Syria (ISIS) branch in Afghanistan are active in Nangarhar.

Earlier on Wednesday, an Afghan official said a roadside bombing had killed at least 11 people on a bus, including women and children, in the country's western Farah province.

Abdul Jabar Shahiq, chief of the province's health department, said the bombing on Tuesday morning in the Bala Buluk district also wounded 31 people, all civilians.

Shahiq says the bus was on its way from Herat province toward the capital, Kabul, when it struck the roadside bomb.

No group immediately claimed responsibility for the bombing but the Taliban have a strong presence in the province, especially in Bala Buluk where they often plant roadside bombs to target government officials or Afghan security forces.

Such attacks often end up inflicting significant casualties among civilians.