"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.
On Thursday morning it was confirmed that two Indian nationals were killed in the terror attack [Indian casualties in Kabul attack, says envoy]