KABUL, Afghanistan -- Hundreds of insurgents launched a large-scale attack Tuesday against Afghan police in a remote mountainous eastern province, a part of the country that is largely under Taliban control, officials said.

Nuristan province police chief Gen. Shams-ul Rahman Zahid said about 400 Taliban fighters armed with AK-47s, heavy machine guns and rocket-propelled grenades unleashed their assault around daybreak, pounding the checkpoints around a base housing police reserve units located about 11 miles (18 kilometers) south of the provincial capital of Parun.

But by late afternoon, Zahir said the checkpoints had held their ground and had been reinforced by more police from Parun.

Afghan forces inspect the Traffic Department building where they Taliban fighters were holding up during two days of clashes in Kandahar May 9, 2011. Afghan troops clashed with the Taliban in the southern city of Kandahar for a second day on Sunday after insurgents launched coordinated attacks with rocket-propelled grenades and suicide raids against government buildings.[Photo/Agencies]

Tuesday's attack is the second significant strike staged by the Taliban on Afghan government forces in less than four days and just one week after US commandos killed al-Qaida leader Osama bin Laden.

The first attack came over the weekend in the southern city of Kandahar, the birthplace of the Taliban and the economic hub of southern Afghanistan, where the Taliban attempted a full frontal assault on government buildings across the city. At least two dozen insurgents, two members of the Afghan security forces and one civilian were killed in two days of gunbattles in the city.

The Taliban have said the Kandahar attacks were planned well before bin Laden's death and were part of their spring offensive.

Zahid, the Nuristan provincial police chief, did not say how many police were under attack Tuesday or the size of the security force based in the province, although it is thought to be small. He cited operational security.

"We have requested from NATO forces and the Afghan army to help. They have not responded yet. I have ordered other units to go and help," Zahid said. He gave no other details on the fighting but said it was ongoing.

NATO said it was not aware of the attacks. There are few coalition or Afghan Army troops in mountainous Nuristan, near the Pakistan border.

The Nuristan and Kandahar attacks are the most ambitious since the insurgents declared the start of a spring offensive against NATO and the Afghan government last month. NATO has been expecting the Taliban to stage a series of spectacular and complex attacks, and the group has already carried out a number of them.

But violence continued in other parts of Afghanistan as well. NATO said Tuesday that three of its service members were killed by roadside bombs, one on Tuesday in the east and two on Monday in the south. NATO did not release further details or their nationalities. So far seven NATO troops have died this month, a total of 158 since the start of the year.

In southern Zabul province, the Afghan Ministry of Defense said one of its commando units killed five insurgents, including two Pakistanis. It also said two armed foreign nationals, a Frenchman and a Moroccan, were detained "along with ammunition, weapons, military equipment and propaganda letters."

It provided no further details on the two foreigners.

In eastern Paktika, the provincial governor's office said six insurgents were killed and another eight captured in Afghan police operation.

In Nuristan, Mohammed Zareen, a spokesman for the provincial governor, confirmed a large attack was under way but had no details on the number of insurgents involved. He said local residents were assisting the police.

"We have only national police in area. We don't have army or NATO forces to support police," he said.

Taliban spokesman Zabiullah Mujahid said Taliban fighters attacked police and that battles were under way.

"There are large attacks by Mujaheddin on four police checkpoints. Gun battles are going on," he said in a message sent to news organizations in Kabul.

The Taliban and other insurgent groups control large swaths of Nuristan, Kunar and other northeastern provinces near the Pakistani border. Insurgents retain safe havens in Pakistan's neighboring lawless tribal regions and cross the border into Afghanistan to attack NATO troops.

Hizb-i-Islami, a militant group made up of loyalists of regional warlord Gulbuddin Hekmatyar, also has a large presence in the region. They are not thought to be taking part in the attacks. The area also has smaller ultraconservative Salafist groups.

Zahir said he had intelligence that the strikes were being carried out by Pakistanis and Arabs who have been crossing the border into Afghanistan.

The Taliban also control the tiny capital Nuristan's rugged Waygal district, which they overran with more than 300 fighters on March 29 and raised the white flag of the Islamic Emirate of Afghanistan _ as the country was known when it was under Taliban control before the 2001 U.S. invasion. Zahir said they also directly control half of Kamdesh district.

"Unfortunately Waygal is still under control of the Taliban. We are waiting for the Ministry of Interior to instruct us. We have not acted to take it back after it collapsed," he said.