Afghanistan's Islamic State affiliate has claimed responsibility for a bombing outside a sports stadium in eastern Nangarhar province that killed three people and wounded 10.

In a statement posted late on Monday on an IS-linked website, the militant group said the motorcycle bombing in the provincial capital of Jalalabad targeted a pro-government meeting.

The explosion occurred as former warlord Gulbuddin Hekmatyar wrapped up a rally at the stadium. Hekmatyar, previously a declared terrorist by the United States, signed a peace deal with President Ashraf Ghani in 2017 and was removed from the list.

The Afghan IS affiliate, known as Khorasan Province, is based in Nangarhar.

A separate militant statement on the IS-affiliate Aamaq news agency gave a different version of events, saying the bomb targeted a bus with pro-government militiamen.