ISLAMABAD (Reuters) -- Pakistani forces consolidated their hold on the main town in the Swat valley on May 31 and began trucking supplies to 40,000 civilians stranded there, as fighting flared in South Waziristan on the Afghan border.
The army said it had captured Mingora on May 30 and troops were out on patrol on May 31.
"Mingora has been fully secured and relief activities have started," the army said in a statement. "Security forces are patrolling in all the important areas of Mingora."
Pakistan has been carrying out its most concerted offensive yet against an expanding Taliban insurgency.
The focus of the Pakistani fighting since late April has been in the former tourist valley of Swat, 120 kilometers (80 miles) northwest of Islamabad, which the Taliban turned into a bastion as authorities alternated between inconclusive military action and peace pacts.
Tension has also been rising in South Waziristan, a major Al-Qaeda and Taliban stronghold, with military officials saying an offensive was likely there after Swat was secured.
The United States and the Afghan government have long been pressing Pakistan to root militants out of South Waziristan and other enclaves on the Afghan border, from where the Taliban direct their Afghan war.
Militants attacked a paramilitary force camp near the town of Jandola, 80 kilometers (50 miles) east of Wana, the main town in South Waziristan, late on May 30 and fighting went on for hours, security officials said.
"They carried out a very serious attack.... It was repulsed after a heavy exchange of fire," said military spokesman Major-General Athar Abbas.
Up to 15 militants and three soldiers were killed, he said.
Ten militants and four soldiers were killed in another clash in South Waziristan when militants ambushed a military convoy late on Saturday, the military said.
Militant violence has surged in Pakistan since mid-2007, with attacks on security forces, as well as on government and Western targets.
The militants have responded to the Swat offensive with eight bomb attacks in various towns and cities and they have threatened more. Main cities are on alert.
The offensive also sparked an exodus of about 2.4 million people, according to government figures, and the country faces a long-term humanitarian crisis. The United Nations has pleaded for contributions for a $543 million fund to help.
Bomb attacks in cities and the plight of the displaced could undermine public support for the offensive but the government and military say they are determined to defeat the Taliban in Swat.
The military said it had distributed 25 tonnes of relief goods for 40,000 people stranded in Mingora, which usually has a population of 300,000.
The military also urged civilians to leave the town of Charbagh, about 15 kilometers (10 miles) north of Mingora, and lifted a curfew there and in Mingora and thousands of people left the two towns.
"We have to flee. I don't know what will happen tomorrow," Mingora resident Mohammad Nisar told Reuters.
Civilians in Swat had no running water or electricity, and faced food shortages and lack of medical facilities, the International Committee of the Red Cross (ICRC) said on May 31.
"The organization is gravely concerned about the plight of civilians in Swat and believes their situation demands a prompt and comprehensive humanitarian response," the ICRC said in a statement.
Secretary of Defense Syed Athar Ali said at a regional defence meeting in Singapore the military operation could be over in two or three days.
But Interior Minister Rehman Malik told Reuters Ali had been referring to the securing of Mingora, not the operation in the whole valley.
The military has been reluctant to predict how long the offensive would last, saying there was still resistance.
"It's very difficult to give a timeline," said Abbas. "It's a very big area so nobody's in a position to give any timeline for the operation."
The military says about 1,220 militants have been killed since late April, while 90 soldiers have been killed and 250 wounded. There are no independent casualty estimates available.