Three rockets smashed into this southern Afghan city early Sunday, jolting residents but causing no casualties, the latest in a string of attacks across the south that have raised fears that Taliban rebels and their Al Qaeda (search) allies are regrouping.

One of the rockets hit an empty lot near the former home of fugitive Taliban leader Mullah Mohammed Omar (search) which now houses U.S. special forces troops, said Gen. Salim Khan, the deputy police chief. The other two hit elsewhere in the city.

Khan blamed Taliban (search) rebels for the attack, which occurred at about 3 a.m.

"The one rocket hit right next to Mullah Omar's home, and two other rockets hit fields in Kandahar city," said Khan. "The Taliban did this. Nobody else would do such a thing."

U.S. troops cordoned off the area next to Mullah Omar's old home, keeping residents and journalists a good distance away.

Meanwhile, a purported Taliban spokesman claimed responsibility for an ambush of a police convoy in southern Afghanistan, and said insurgents had killed a district police chief after taking him captive. Mullah Latif Hakimi said the man was killed for collaborating with the U.S.

Ten other officers taken captive in the ambush on Thursday were still alive, he said.

Hakimi often calls news organizations to claim responsibility for attacks on behalf of the Taliban. His information has sometimes proven untrue or exaggerated, and his exact tie to the group's leadership is unclear.

In other violence, rebels attacked a government office Saturday in Zabul province's Daychopan district and an ensuing two-hour gunbattle left four insurgents dead, said provincial spokesman Ali Khail. The attackers fled after U.S. helicopters arrived to back up the Afghan troops on the ground, he said.

On Friday, rebels detonated a bomb hidden next to a road in nearby Helmand province as a government vehicle was passing, said Mohammed Wali, spokesman for the provincial governor. A soldier in the vehicle was killed, he said.

In Kandahar province's Shah Wali Kot district, fighting Friday between Afghan soldiers and Taliban rebels left two insurgents dead, local army commander Gen. Muslim Amid said.

Attacks across the country have increased since March, when snow melted on mountain passes used by the insurgents. About 240 suspected rebels and 29 U.S. troops have been killed in the recent violence, according to Afghan and U.S. officials.