At least 27 people have been killed after a hotel in the Tunisian coastal city of Sousse came under attack by unidentified gunmen. 

An interior ministry official said that tourists were among those who had been killed in Friday's attack.
One attacker had been killed by police and a search operation was ongoing, with reports that another attacker was involved.
Ongoing exchanges of gunfire had earlier been reported between the attackers and security forces, sources told Al Jazeera. 
The attack was on the Imperial Marhaba hotel, local radio said, according to the Reuters news agency. Other reports indicated that two hotels may have been attacked.
Al Jazeera's Nazanine Moshiri, reporting from Tunis, said that local reports indicated that gunmen may have specifically targeted tourists at the resort - but that the reports have not yet been confirmed.
She said that the death toll was expected to rise.
There were no other details immediately available.
Tunisia has been on high alert since March when gunmen attacked the Bardo museum in Tunis, killing a group of foreign tourists in one of the worst attacks in a decade in the North African country.
Our correspondent said that the new attack would be another blow to the country's economy, which relies heavily on tourism. 

The attack was on the Imperial Marhaba hotel, local radio said, according to the Reuters news agency