Denmark's premier, whose country is a key player in an international operation to destroy Syria's chemical arsenal, said Wednesday she was "cautiously optimistic" the timetable for doing so will be met.

Helle Thorning-Schmidt was speaking during a meeting with Cypriot President Nicos Anastasiades aboard the Danish frigate HDMS Esbern Snare, which is escorting Syrian chemical weapons shipments and is operating out of nearby Cyprus.

The Spanish government said Wednesday it has approved the extradition to Kazakhstan of the former chief of security of a Kazakh banker-turned-dissident despite warnings from rights groups that he will face torture.

Aleksandr Pavlov was arrested in Spain in December 2012 after his name was placed on Interpol's wanted list at the request of Kazakh authorities who accuse him of embezzlement and plotting terrorist attacks. He denies the allegations against him.

U.S. President Barack Obama on Wednesday warned of "consequences" over the violence in Ukraine and said it held the government responsible for ensuring that its people can protest "without fear of repression."

"We hold the Ukrainian government primarily responsible for making sure that it is dealing with peaceful protesters in an appropriate way, that the Ukrainian people are able to assemble and speak freely about their interests without fear of repression," Obama said during a visit to Mexico.

Rebels rained rockets on the capital of Sudan's South Kordofan state on Wednesday, official radio reported, a day after peace talks with the government broke off.

"SPLM-North shelled Kadugli with Katyusha (rockets)," Radio Omdurman said in a brief SMS dispatch citing the state's governor.

Russian Foreign Minister Sergei Lavrov in a phone call to his German counterpart Frank-Walter Steinmeier called for the European Union to encourage the opposition to cooperate with the authorities.

Steinmeier is heading to Ukraine on Thursday with the French and Polish foreign ministers before emergency talks among EU ministers in Brussels.

U.S. President Barack Obama arrived in Mexico Wednesday for a summit with the Mexican and Canadian leaders focused on trade but marked by some frictions between the North American trio.

Obama was greeted by Mexican Foreign Minister Jose Antonio Meade at the airport in Toluca, near Mexico City, before heading to the local state government palace for talks with President Enrique Pena Nieto and Canadian Prime Minister Stephen Harper.

A U.S. citizen dubbed a "lone wolf" terrorist and al-Qaida sympathizer has pleaded guilty to plotting to bomb targets in New York and kill U.S. soldiers, prosecutors said Wednesday.

Jose Pimentel, 29, a Muslim convert born in the Dominican Republic, will be sentenced on March 25, the New York district attorney's office said.

Austria's president has been invited to Iran, his office said Wednesday, in what would be the first visit by a Western head of state since President Hassan Rouhani's election.

"Yes it is correct that the president (Heinz Fischer) has been invited to Iran," spokeswoman Astrid Salmhofer told Agence France Presse. She declined to comment on whether the invitation would be accepted.

Canada closed its embassy in Kiev on Wednesday after fierce clashes left at least 26 people dead in Ukraine, where anti-government protesters were locked in a stand-off with riot police.

"As a security precaution, and to ensure the protection of all staff, our mission in Kiev will be closed until further notice," foreign ministry spokesman Adam Hodge told Agence France Presse.

U.N. refugee agency chief Antonio Guterres on Wednesday urged the international community to keep up aid for Afghan refugees, stressing that 2014 with the departure of NATO troops was a critical year for their homeland.

"2014 is key to Afghanistan's stability. The world cannot afford an unsuccessful Afghan transition," said the United Nations High Commissioner for Refugees at the end of a two-day visit to Iran.