<p>The United States has not seen any additional attacks or responses in the past 36 hours in Syria, White House spokesman John Kirby said on Monday.</p>.<p>He said the United States remains vigilant after an attack on a US base in Syria on March 23 that killed an American contractor, wounded another and hurt five US troops. </p>
<p>The United States has not seen any additional attacks or responses in the past 36 hours in Syria, White House spokesman John Kirby said on Monday.</p>.<p>He said the United States remains vigilant after an attack on a US base in Syria on March 23 that killed an American contractor, wounded another and hurt five US troops. </p>