The United States has seen a significant reduction in violence in Afghanistan during the past six days, Secretary of State Mike Pompeo said on Friday, one day before Washington hopes to sign a U.S.-Taliban deal on an American troop withdrawal.Pompeo's remark suggested that if the lull continues for a full week as intended, it will be possible to sign the pact as part of a wider effort to promote intra-Afghan reconciliation and to end the United States' longest war.