(CNN) -- Clashes between hard-line Islamists and government forces killed six people and wounded 19 in Mogadishu on Friday as violence gripped the Somali capital for a third consecutive day.

A shell hit a bus station in the northern part of the city, causing several of the casualties, said Ali Muse, director of a local ambulance group. Another shell landed near a mosque in southern Mogadishu, he told CNN.

The heaviest shelling centered on mostly deserted neighborhoods where fighters from the al Qaeda-linked Al-Shabaab group are in control.

At least 32 people have been killed in the three days of heavy fighting, including a patient waiting for treatment at a hospital. Earlier, eight journalists at an Al-Shabaab news conference were critically wounded.

The U.N. High Commissioner for Refugees estimates that more than 200,000 Somalis have been forced to flee their homes this year, with most remaining within the country's borders because of heavily guarded checkpoints and difficulties in accessing transportation out.

"Those who reach safety abroad speak of a dire situation inside the country," U.N. refugee agency spokesman Adrian Edwards said in a written statement.

He said insecurity and lack of access is making it hard for humanitarian agencies to reach millions of people in need.

Journalist Mohamed Amiin Adow contributed to this report.