Operations being conducted by Pakistan's military in North Waziristan and Khyber tribal regions have forced al Qaeda, Islamic State (IS) and Islamic Movement of Uzbekistan (IMU) to move into Afghanistan, a Wall Street Journal report quotes Afghan officials and locals as saying.

At least 400 IMU and al Qaeda-affiliated families crossed into Afghanistan last month, who now live in the homes of locals in lawless parts of the country, Afghan officials say.

Read: Kabul asked not to shelter fleeing NWA tribesmen

Haji Abdul Azizi, a tribal elder from Helmand province’s Sangin district, tell WSJ that he hosted a family of Arabic speakers for a night who claimed to be IS loyalists.

"They were six men, seven women and two children, some of whom spoke Pashto", according to Azizi, who added that the "women of the group were armed and took turns keeping watch on each other during the night".

The newcomers try to enforce their own brand of Islam which clashes with local traditions, he added.

Also read| Zarb-e-Azb operation: 120 suspected militants killed in N Waziristan

Afghan officials said that the armed outsiders, traveling with families, have settled in Ghazni, Zabul and Farah provinces. They attributed the influx of militants on the operation being conducted by Pakistan's military across the border.

Tribal elders say that the migrating militants have occupied houses, which were previously vacant, with the assistance of the local Taliban.

A senior Afghan security official said the central government is monitoring the presence of these groups, while a spokesman for international forces in Kabul said that while they had no firsthand knowledge of foreign militants’ activities in Zabul or Ghazni,

The militants who moved in Farah province, and are said to be wealthy, have rebranded themselves under the banner of the IS and have also set up training centres in the locality, Khak-e Safid district’s governor Abdul Khaliq Noorzai said.

“They haven’t fought against Taliban or government yet, but they are actively busy with training,” Gul Ahmad Azimi, a senator from Farah, told the WSJ.

The US military maintains a limited presence in Afghanistan, US and coalition officials say they have limited visibility into militant activity in the country’s hinterlands after the withdrawal of combat troops.