Libyan government forces intensified shelling of rebels in the eastern city of Ajdabiya on Saturday, while rebels started to strike back with their heavy weaponry in trying to hold the town between capital Tripoli and their stronghold of Benghazi.

Pan-Arab Al-Jazeera TV reported that government forces had stormed into the city after the heavy shelling.

Fearing the government assault, thousands of civilians and anti-government fighters had fled Ajdabiya Thursday.

According to U.N. figures, more than 400,000 refugees have fled the violence in Libya in the past month.

With fighting intensifying over the past two weeks and casualties rising, the Red Cross said Saturday it was extending its activities to western Libya.

"We are sending a ship to support Misrata's main hospital, to deliver enough medical supplies to treat 300 patients with weapon injuries on the spot," said Jean-Michel Monod, head of the International Committee of the Red Cross team in Tripoli.

Clashes between government troops and rebel forces continued Friday in the coastal city of Misrata. The rebels said they repulsed an attack by the government troops on the eastern flank of the city.

Government armor also attacked areas around Misrata's strategically important Tripoli road.

Misrata has experienced fighting for more than 40 straight days, leaving hundreds dead and wounded and thousands stranded.

Meanwhile, international efforts continued to gain momentum to seek a political solution to the ongoing crisis.

A group of African leaders are expected to visit Libya over the weekend on behalf of the African Union to mediate an immediate ceasefire between Libya's government troops and the rebel forces, the South African foreign ministry said Friday.

During their stay in the violence-torn country, South African President Jacob Zuma and leaders of several other African countries will meet with Libyan leader Muammar Gaddafi in Tripoli and with rebel leaders in the eastern city of Benghazi, according to the ministry.

"Key on the agenda of both meetings will be the immediate implementation of a ceasefire from both sides and the opening of a political dialogue between the two parties," the ministry said.

U.N. Secretary-General Ban Ki-moon will also travel to Egypt to chair a meeting on Thursday over the situation in Libya, his spokesman Martin Nesirky told reporters Friday.

"In an effort to coordinate the international response on Libya, the secretary-general will chair a meeting of concerned international and regional organizations to be held at the League of Arab States headquarters in Cairo on Thursday, the 14th of April," he said.

"The objective of the meeting will be to exchange views and enhance coordination among the participating organizations in addressing the current crisis in Libya," he said.