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By Sharafuddin Sharafyar
HERAT, Afghanistan, Oct 26 (Reuters) - A roadside bomb killed four Afghan police, including a district police chief, in western Afghanistan on Tuesday, the second serious attack this week in what was once a relatively secure area.
The top police officer in the Obe district of western Herat province and three of his colleagues were killed on a road near the border with Iran and Turkmenistan, said Naqibullah Arveen, a spokesman for Herat's governor.
Violence has risen across Afghanistan, with civilian and military casualties reaching record levels this year as the Taliban-led insurgency spreads out of traditional strongholds in the south and east into the once stable north and west.
Arveen blamed the Taliban for the latest attack in Herat, but the Islamist militants did not immediately make any claim of responsibility.
Herat has been seen by NATO-led forces and Western officials as one area where the process of gradually transferring security responsibility from foreign troops to Afghan forces could commence soon.
On Sunday, however, at least four suicide bombers dressed as women and police officers attacked the main U.N. compound in Herat city, one of Afghanistan's largest and an important commercial hub.
All the insurgents were killed and no U.N. staff were hurt, but the raid renewed fears over security in the area despite U.N. and Afghan officials saying that Afghan forces dealt with the attack effectively.
Despite the presence of about 150,000 foreign troops, violence is at its worst since the Taliban were ousted by U.S.-backed Afghan forces in 2001, with the Taliban broadening the scope and size of their attacks in recent years.
In response, NATO-led forces -- primarily from the United States -- have stepped up raids across the country in recent months, the operations leading to the capture and killing of hundreds of suspected militants, mostly in the south and east.
The rising violence will likely weigh heavily on U.S. President Barack Obama when he reviews Washington's Afghanistan war strategy in December.
On Tuesday, the NATO-led International Security Assistance Force (ISAF) said Afghan and alliance forces had captured a Taliban leader blamed for involvement in the kidnapping and subsequent killing of two U.S. sailors in July.
It did not identify the man arrested in eastern Logar province on Monday. (Additional reporting and writing by Sayed Salahuddin in KABUL; Editing by Paul Tait and Ron Popeski)
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