By Jalil Ahmad
HERAT, Afghanistan (Reuters) - Insurgents launched an attack near a foreign base in the largest city in Afghanistan's west on Monday, Reuters witnesses said, with several casualties feared and gunfire ringing out across the city.
One Reuters witness reported seeing the bodies of several troops wearing foreign uniforms and saw smoke rising near the Italian-run joint civilian and military provincial reconstruction team (PRT) base in Herat.
A second Reuters witness said it appeared an unknown number of insurgents had entered a seven-storey building near the PRT and began opening fire on the base from there.
Italian troops form the bulk of the NATO-led International Security Assistance Force (ISAF) in the area but there was no immediate confirmation of casualties from ISAF.
A spokesman for ISAF in Kabul said the force was aware of reports of the attack and was looking into them.
Television pictures from Herat showed at least two vehicles destroyed by explosions and troops scurrying for cover
Violence has spiked across Afghanistan since the Taliban announced at the beginning of May the start of a spring offensive.
Attacks have taken place in cities across Afghanistan in recent weeks, with the Afghan government and security forces and foreign military targets singled out in increasingly bold assaults.
U.S. commanders had warned to expect a surge in violence as insurgents attempted to hit back after U.S.-led ISAF troops and Afghan forces made major gains in operations in the Taliban heartland in the south over the past 12 months.
Italy has about 3,880 troops serving in Afghanistan, the majority of them in the west.
(Additional reporting by Hamid Shalizi in KABUL; Editing by Paul Tait and Robert Birsel)