Thomas told reporters at the Pentagon that the increased emphasis on defensive measures to protect US troops on the ground in Syria led to a slight and temporary decline in offensive USA airstrikes against IS in Syria.
Arriving for talks with G7 foreign ministers in Lucca in Italy, Mr Johnson issued a fresh appeal to Russian president Vladimir Putin to abandon his backing for his Syrian ally following last week's chemical weapons attack on a rebel-held town. "I welcome this renewed harmony".
Russian Federation has rejected accusations that Assad used chemical arms against his own people and has said it will not cut its ties with the Syrian president, who has been locked in a six-year-old civil war that has devastated his country.
"The military campaign is focused on. breaking ISIS, defeating ISIS in Syria", Mattis told reporters in his first Pentagon news conference as President Donald Trump's defense chief.
He said: "So Russia faces a choice: it can continue acting as a lifeline for Assad's murderous regime, or it could live up to its responsibilities as a global power, and use its influence over the regime to bring six long years of failed ceasefires and false dawns to an end". And others in the Trump administration cautioned that final American determination had been made that Russian Federation had advance knowledge of the attack, which killed more than 80 people and prompted retaliatory US cruise missile strikes.
Tillerson is traveling Tuesday to Moscow.
Investors play safe around the world as Syria tensions rise
The dollar fell in Asian trading on Tuesday, as concerns over tensions with North Korea and Syria weighed on U.S. Emerging market stocks were down 0.4 percent, on track for their fourth straight day of declines.
It's a clear mission, McConnell said.
Tillerson made plain that the chemical attack last week in Syria was unacceptable to the USA, and that the US retaliatory missile strike against a Syrian base presented Russian Federation with a choice: either continue to side with Syria, Iran and the militant group Hezbollah, or join with the US and other likeminded countries. But well before his plane landed on the runway, heated words were already flying between the US secretary of state and Russian officials over the situation in Syria.
"Lavrov stressed that an attack on a country whose government is fighting terrorism only plays into the hands of extremists creates additional threats to regional and global security", the statement said. "They plan to plant some chemical there and accuse the Syrian government of an attack", RT reported Putin said.
A two-day summit of G7 ministers in Italy ended in division over Syria, as the United Kingdom proposed - without success - sanctions against Syrian and Russian military figures over the chemical attack.
Another U.S. official cautioned that no final American determination has been made that Russian Federation knew ahead of time that chemical weapons would be used. He said the United Nations should first investigate the attack.
"It was a very deliberate, very proportional, and very targeted strike undertaken in response to the chemical weapons attack", said Secretary of State Rex Tillerson.