"In the aircraft I got news about the attack in Kabul. Am concerned about the situation & I pray for everyone's safety," Modi tweeted as he boarded Air India One here for China on a three-day visit.
"Three to four gunmen entered Park Palace guesthouse in the evening," a senior Afghanistan security official told AFP in Kabul.
Several people were reportedly trapped inside the guesthouse as the Taliban press on with their annual spring offensive.