Dozens of militants attacked three army posts in a tribal region that serves as the primary base for Pakistan's Taliban chief, triggering shootouts that left 20 insurgents and three soldiers dead early Thursday, intelligence officials told The Associated Press. The clashes in South Waziristan, a rugged, remote region along the Afghan border where al-Qaida and the Taliban have long had strongholds, came amid rumblings that the Pakistani military will launch a new offensive there - something that would please U.S. officials who want to eliminate cross-border threats to troops in Afghanistan. In the southwest of the country, a bomb exploded in the toilet of a passenger train on the move from Quetta to Karachi, killing one and wounding 35 others, police official Shamar Ali Magsi said. The Baluch Republican Army, a nationalist group fighting a low-level insurgency for greater autonomy for Baluchistan province and a bigger share of its oil revenues, claimed responsibility for the blast, spokesman Sarboz Baluch said in a phone call to The Associated Press. Deadly attacks have risen sharply across Pakistan in the past two weeks and are being blamed on militants who have vowed a campaign of bombings in retaliation for the military's offensive to oust the Taliban from the northwestern Swat Valley region. On Tuesday, a suicide bombing at a luxury hotel in the main northwest city of Peshawar left nine dead. Army officials say Taliban fighters are attacking soldiers in South Waziristan to distract the military from its operation in Swat, where they say they have killed more than 1,300 militants since late April. But none will rule out an offensive in South Waziristan, the main base for Pakistani Taliban chief Baitullah Mehsud, who is allied with al-Qaida. The coordinated attacks early Thursday targeted bases in Jandola, Chakmalai and Splitoi towns in South Waziristan, said two intelligence officials who spoke on condition of anonymity because they were not authorized to speak to media. The militants used rockets and guns, prompting troops to return fire, the officials said. No army spokesman could immediately be reached to confirm the incident, and few other details were available. Journalists are heavily restricted from traveling to the region, and its dangerous nature further complicates independently verifying information from there. Meanwhile, army helicopter gunships targeted militant positions in the northwest Bannu, Hangu and Upper Dir regions Thursday, killing two local Taliban commanders and some of their associates, three other intelligence officials said. And a citizens militia continued an exchange of fire with Taliban in two Upper Dir villages, said the officials, who also sought anonymity as they were not authorized to speak to media. Past offensives against Islamist militants - including in South Waziristan - have often faltered, with the government choosing to strike peace deals with the extremists. It tried that route with militants in Swat, only to see the Taliban there gain more strength and control. Taliban advances out of Swat and into a district just 60 miles (100 kilometers) from the capital, Islamabad, earlier this year helped turn public opinion more in favor of military action. Now the army says it controls most of the Swat valley and surrounding districts. In the wake of the Peshawar Pearl Continental hotel bombing, government officials have tried to rally public opinion in favor of taking on the militants. "This is a war, but the people of this country will not bow to the cowardly acts of terrorists. People are now seeing the real face of those who have been exploiting them in the name of Islam," North West Frontier Province senior minister Bashir Ahmad Bilour Bilour told reporters Wednesday. In Washington, President Barack Obama's special envoy to the region, Richard Holbrooke, said Wednesday that he was observing "the slow emergence of a consensus behind the government's actions." Political analyst Hasan-Askari Rizvi said overall sentiment was nuanced, but it appeared support for the Taliban was waning. "Among ordinary Pakistanis, the state of mind is changing only to the extent that they are more afraid," Rizvi said. "Some people will start saying stop the operations and others will argue that you should take firm action against them. While ordinary people might sometimes have contradictory thinking, overall I would say the balance is tilting against the Taliban."