John Kerry says that the largest threat to Ukraine is Russian aggression but that the west is not seeking conflict with Russia.
The Secretary of State says the US is seeking a diplomatic solution to the conflict in Ukraine but is not prepared to "close our eyes" to Russian tanks and fighters crossing the border.
Speaking after talks in Kiev with Ukrainian President Petro Poroshenko, Kerry demanded an immediate commitment by Moscow to a ceasefire in eastern Ukraine that was backed up by actions on the ground.
Russia has consistently rejected accusations from Kiev and the West that it supports a pro-Russian rebellion in eastern Ukraine with troops and heavy weaponry.
The US has pledged $16.4 million in humanitarian aid to help civilians in eastern Ukraine.
Secretary of State John Kerry arrived in Kiev this morning for talks with the embattled Ukrainian leadership.
US Secretary of State John Kerry has written on Twitter:
US Secretary of State John Kerry has said that the insurgency by Islamic State militants in northern Iraq and Syria demands a "much fuller response" than just airstrikes.
Writing in the New York Times, he said:
Airstrikes alone won’t defeat this enemy. A much fuller response is demanded from the world. We need to support Iraqi forces and the moderate Syrian opposition, who are facing ISIS on the front lines ... In this battle, there is a role for almost every country. Some will provide military assistance, direct and indirect. Some will provide desperately needed humanitarian assistance for the millions who have been displaced and victimized across the region. Others will help restore not just shattered economies but broken trust among neighbors.
US secretary of state John Kerry warned today that the violent acts carried out by Islamist militants in Iraq "show all the warning signs of genocide"
"With the potential of further executions taking place," he said, "and because people are a minority huddled for safety on a mountain top, the United States has made its decision that it must save these lives.
"The world needs to join us in the condemnation of these actions," Mr Kerry added, speaking in the Afghan capital of Kabul.
US Secretary of State John Kerry has arrived in Vienna for talks with foreign ministers about Tehran's nuclear program.
Iran and the six powers- Britain, the US, France, Germany, Russia and China- aim to reach a long-term deal to end the decade-old nuclear standoff by July 20.
US Secretary of State John Kerry has said all of the reports of fraud and irregularities in the second round of the Afghan presidential vote need to be resolved.
The election run-off between the leading contenders, Abdullah Abdullah and Ashraf Ghani, has been deadlocked since the June 14 vote, raising concerns in Washington about a smooth transition of power in Afghanistan just as US troops are withdrawing.
Abdullah Abdullah has declared he was the winner of last month's run-off vote, despite preliminary results showing that Ashraf Ghani won the second round.
US Secretary of State John Kerry will travel to Vienna this weekend to try to break the deadlock in negotiations over Iran's nuclear programme, a senior Western official told Reuters.
The source, who spoke on condition of anonymity, said: "I can tell you that Kerry will be in Vienna this weekend, probably on Saturday."
However, the official added it was unlikely there would be an agreement signed in the near future, given the disagreements between Iran and western nations over Tehran's nuclear programme.
Financial and military aid to Afghanistan would be cut if any party tries to seize power illegally, US Secretary of State John Kerry has said.
The warning comes after Afghan presidential candidate Abdullah Abdullah claimed he was the winner of last month's run-off vote, despite preliminary results showing that Ashraf Ghani won the June 14 second round.
Thousands of Abdullah's supporters gathered in Kabul with some suggesting his camp should declare victory and form a parallel government.
“I have noted reports of protests in Afghanistan and of suggestions of a ‘parallel government’ with the gravest concern,” said Mr Kerry in a statement during a trip to Asia.
US Secretary of State John Kerry has made the highest-level American visit to Egypt since President Abdel-Fattah el-Sissi took office in an attempt by Washington to press the country for more moderate policies.
Kerry said the US government has proposed providing an aid package worth $650 million (£380m) to Egypt and is working with Congress to settle differences over the final amount
Earlier this month, the US quietly agreed to send an estimated $572 million US dollars to Egypt in military and security assistance - widely believed to include Apache attack helicopters- on top of $200 million US dollars in economic aid already delivered.