SHANGHAI, China — North Korean leader Kim Jong Il reportedly visited Shanghai today, prompting speculation the rare foray to his country's closest ally might signal a willingness to resume talks over Pyongyang's nuclear program.

None of the reports of a visit could be independently confirmed, and there was no sign of any unusual activity or added security in China's commercial hub.

China has in the past announced the secretive Kim's visits only after he has returned to North Korea. His last visit was in early 2004.

Reports of Kim's latest visit first emerged Tuesday, when South Korean media and officials said his train had crossed the border into China.

Experts on North Korea said a visit could signal the hard-line communist regime was considering dropping its refusal to resume six-nation nuclear talks.

SEOUL, South Korea — South Korea's top university today apologized for the scandal over stem cell scientist Hwang Woo-suk's faked research, calling it a blemish on the country that embraced him as a national hero.The government said it would withdraw Hwang's "top scientist" title — an honor created especially for him in the wake of purported breakthroughs that raised hopes for using stem cells to develop new treatments of diseases from Alzheimer's to diabetes.Seoul National University's apology came a day after its investigative panel confirmed that Hwang faked all of his human stem cell research, including his landmark 2004 claim in the journal Science that he cloned a human embryo and extracted stem cells from it.

BAGHDAD, Iraq — The most influential politician in Iraq issued a veiled warning today to Sunni Arabs that Shiites would not allow substantive amendments to the country's new constitution, including to the provision that keeps the central government weak in favor of strong provincial governments.Abdul Aziz al-Hakim, the leader of the Supreme Council for the Islamic Revolution in Iraq, or SCIRI, said in an address in honor of the Islamic holiday of Eid al-Adha that provincial governments will remain strong in the constitution, which can be amended after the next government is installed."The first principle is not to change the essence of the constitution. This constitution was endorsed by the Iraqi people," he said.Sunni Arabs place great stock in their ability to change the constitution, one of the reasons Sunni politician urged the minority to turn out in large numbers during the Dec. 15 parliamentary election.They want a stronger central government because the constitution now bestows most power — including control over oil profits — to provincial governments. The Shiites in the south and the Kurds in the north control most of Iraq's oil. There are few oil reserves in central Iraq, where Sunnis live.By The Associated Press