KABUL, March 1 (Reuters) - Blasts and gunfire were heard in Kabul on Sunday, a Reuters journalist in the Afghan capital said, as fighting between Afghanistan and Pakistan entered a fourth day.
Explosions echoed across parts of the city before sunrise, followed by bursts of gunfire, the journalist said.
It was not immediately clear what had been targeted or whether there were casualties.
Taliban administration spokesperson Zabihullah Mujahid said the sounds were the result of Afghan forces targeting Pakistani aircraft over the capital.
"Air defence attacks were carried out in Kabul against Pakistani aircraft. Kabul residents should not be concerned," Mujahid said.
Pakistan's prime minister's office, information ministry and military did not respond to requests for comment.
The violence follows air strikes inside Afghanistan this week that Pakistan said targeted militant infrastructure. Afghanistan described the strikes as a violation of sovereignty and announced retaliatory operations along their shared border.
Both sides have reported heavy losses, issuing differing casualty figures that Reuters has not been able to independently verify.
The engagement is among the neighbours' most violent in years and raises fear of a broader conflict along their 2,600 km (1,615 mile) frontier.
(Reporting by Mohammad Yunus Yawar in Kabul and Rajveer Singh Pardesi in Bengaluru; Editing by Christopher Cushing)
