Explosion heard in downtown Kabul - witnesses

KABUL - 21 August 2017: A rocket struck the heart of Kabul's government and diplomatic area on Monday night, setting off alarms and sirens at foreign embassies, but there were no immediate reports of casualties.

Police said the rocket landed on a secure road just outside the presidential palace and near an area housing other Afghan government offices, foreign embassies as well as the headquarters of the international military coalition.

The blast was preceded by "incoming" announcements on loudspeakers, often used by the American embassy to warn of an imminent rocket attack.

There was no immediate claim of responsibility but Taliban and Islamic State militants have stepped up attacks on the Afghan capital, making it the country's deadliest city for civilians this year.

Monday's rocket strike came just hours before U.S. President Donald Trump was to give a prime-time speech outlining the future of the American presence in Afghanistan.

U.S. military commanders have asked for several thousand more troops to help train and assist Afghan security forces struggling to contain the growing Islamist insurgency.