Policeman Killed in Suicide Bombing outside US Embassy in Tunis

One policeman was killed and others were wounded on Friday when two militants on a motorbike blew themselves up outside the US embassy in Tunisia, authorities said, in the country's most serious attack since the summer.

Embassy officials confirmed the attack in a tweet on its official Twitter feed, and urged people to avoid the area.

The explosion took place near the embassy's main gate, where a Reuters journalist saw a scorched, damaged motorbike and a damaged police vehicle lying amid debris as police gathered around and a helicopter whirled overhead.

The Interior Ministry said two militants were killed carrying out the attack and five police officers were injured, while a civilian suffered minor injuries. State news agency TAP reported that one policeman was killed.

We heard a very powerful explosion ... we saw the remains of the terrorist lying on the ground after he went on the motorbike towards the police," said Amira, a shopkeeper.

Sirens could be heard on the major highway linking the Lac district, where the embassy is located, with Tunis and suburbs in the north.

Roads around security installations were closed in some parts of the capital, and some international institutions were put on lockdown or evacuated.

Last summer, ISIS said it was behind three militant blasts in the capital, including one near the French embassy that killed a policeman and another that wounded five people during a security operation to detain a suspect.

Diplomats who have worked with Tunisia on its security capacity say it has grown more effective in preventing and responding to militant attacks in recent years.